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CORK Bibliography: Drug Use and Gateway Hypothesis

66 citations. 2003 to present

Prepared: June 2011

Agrawal A; Neale MC; Prescott CA; Kendler KS. Cannabis and other illicit drugs: Comorbid use and abuse/dependence in males and females. Behavior Genetics 34(3): 217-228, 2004. (70 refs.)

Cannabis and other illicit drugs are often used or abused comorbidly. Two competing theories to explain this comorbidity are (i) the phenotypic causation (gateway) model and (ii) the correlated liabilities model. We used data from 1191 male and 934 female same-sex twin pairs to test 13 genetically informative models of comorbidity. Models were fit separately for use and abuse/dependence in both sexes. The correlated liabilities model provided a good fit to the data for cannabis and other illicit drug use, as well as abuse/dependence. The relationship between the use or abuse of cannabis and other illicit drugs is not entirely phenotypic, as depicted by the random multiformity of cannabis model, which is an adaptation of the gateway model. The comorbidity appears to arise from correlated genetic and environmental influences. There is some evidence for a model in which high-risk cannabis users may be at increased risk for other illicit drug use. For abuse/dependence, a model with causal pathways between the liability for cannabis and other illicit drug abuse/dependence also fits well. Overall, our results suggest that the use and abuse/dependence of cannabis and other illicit drugs are strongly linked via common risk factors that jointly influence their individual liabilities.

Agrawal A; Silberg JL; Lynskey MT; Maes HH; Eaves LJ. Mechanisms underlying the lifetime co-occurrence of tobacco and cannabis use in adolescent and young adult twins. Drug and Alcohol Dependence 108(1-2): 49-55, 2010. (66 refs.)

Using twins assessed during adolescence (Virginia Twin Study of Adolescent Behavioral Development: 8-17 years) and followed up in early adulthood (Young Adult Follow-Up, 18-27 years), we tested 13 genetically informative models of co-occurrence, adapted for the inclusion of covariates. Models were fit, in Mx, to data at both assessments allowing for a comparison of the mechanisms that underlie the lifetime co-occurrence of cannabis and tobacco use in adolescence and early adulthood. Both cannabis and tobacco use were influenced by additive genetic (38-81%) and non-shared environmental factors with the possible role of non-shared environment in the adolescent assessment only. Causation models, where liability to use cannabis exerted a causal influence on the liability to use tobacco fit the adolescent data best, while the reverse causation model (tobacco causes cannabis) fit the early adult data best. Both causation models (cannabis to tobacco and tobacco to cannabis) and the correlated liabilities model fit data from the adolescent and young adult assessments well. Genetic correlations (0.59-0.74) were moderate. Therefore, the relationship between cannabis and tobacco use is fairly similar during adolescence and early adulthood with reciprocal influences across the two psychoactive substances. However, our study could not exclude the possibility that 'gateways' and 'reverse gateways', particularly within a genetic context, exist, such that predisposition to using one substance (cannabis or tobacco) modifies predisposition to using the other. Given the high addictive potential of nicotine and the ubiquitous nature of cannabis use, this is a public health concern worthy of considerable attention.

Alter RJ; Lohrmann DK; Greene R. Substitution of marijuana for alcohol: The role of perceived access and harm. Journal of Drug Education 36(4): 335-355, 2006. (30 refs.)

Research has shown significant declines in gateway drug use among participants in a school/community substance abuse prevention intervention in a midwestem, suburban school district (Lohrmann, Alter, Greene, & Younoszai, 2005). Though still at or below national levels, student marijuana use was not impacted as positively. The current study investigated the possibility that efforts to prevent alcohol use resulted in an unintentional substitution effect thereby increasing marijuana use. Factors including perceived access to alcohol and marijuana, along with perceived harm associated with alcohol and marijuana use, were examined to determine their role in marijuana use. Findings revealed a relationship between perceived access to and perceptions of harm associated with marijuana and its use that depended on the level of perceived access to and harm associated with alcohol.

Amos A; Wiltshire S; Bostock Y; Haw S; McNeill A. 'You can't go without a fag . . . you need it for your hash': A qualitative exploration of smoking, cannabis and young people. Addiction 99(1): 77-81, 2004. (24 refs.)

Aims: To examine the relationship between smoking tobacco and cannabis use among smokers in their mid-to-late teens. Design and participants: Two qualitative studies in Scotland. One study used semistructured paired interviews involving 99 16-19-year-old smokers, the other comprised eight focus groups involving 46 15-16-year-old smokers. Measurement: The interviews and focus groups explored the role and meaning of smoking in the participants' lives, smoking histories and future cessation intentions and how these related to other aspects of their lives, particularly cannabis use. Findings: Cannabis use was regarded as an important and enjoyable aspect of many of the participants' lives. Importantly, cannabis use and cigarette smoking were linked inextricably. Several reported how smoking joints had been a 'gateway' to smoking cigarettes. While most wanted to quit smoking cigarettes, cannabis use reinforced their cigarette smoking and few wanted to stop using cannabis. Conclusion: National studies need to be conducted to examine how widespread the problem identified is and tobacco control initiatives and smoking cessation treatment services need to consider urgently how to overcome the barrier that a desire on the part of young people to continue cannabis smoking poses to achieving a reduction in tobacco use.

Arabi Z. An epidemic that deserves more attention: Epidemiology, prevention, and treatment of smokeless tobacco. Southern Medical Journal 100(9): 890-894, 2007. (55 refs.)

Smokeless tobacco (ST) use is common, especially in southern and rural areas. It is expected to become more popular with the recent move to sell more ST in areas where indoor smoking is banned. ST use usually starts in adolescence, which places this group at high risk. Nicotine dependence occurs almost exclusively in people who start using ST in their adolescent years, so it is crucial to prevent the introduction of ST to this age group. The debate over whether ST is a gateway to smoking or a bridge to quitting has not been fully answered. ST should not replace smoking where indoor smoking is banned. ST is less harmful than smoking, but nicotine replacement therapy (NRT) is much safer than ST. NRT and bupropion are helpful in the treatment of ST dependence by decreasing withdrawal symptoms and preventing weight gain after cessation.

Bates C; Fagerstrom K; Jarvis MJ; Kunze M; McNeill A; Ramstrom L. European Union policy on smokeless tobacco: A statement in favour of evidence based regulation for public health. Tobacco Control 12(4): 360-367, 2003. (24 refs.)

Rationale: This statement is an updated version of one released by the same authors in February 2003. The statement was produced to follow up the Royal College of Physicians (RCP) Tobacco Advisory Group report "Protecting smokers, saving lives: the case for a tobacco and nicotine regulatory authority", (1) which argued for an evidence based regulatory approach to smokeless tobacco and harm reduction and posed a series of questions that regulators must address in relation to smokeless tobacco. The purpose of this statement is to provide arguments of fact and principle to follow the RCP's report and to outline the public health case for changing existing European Union (EU) regulation in this area. A review of regulation in relation to harm reduction and regulation of tobacco products other than cigarettes is required in Article 11 of EU directive 2001/37/EC,(2) and this is a contribution towards forming a consensus in the European public health community about what policy the EU should adopt in the light of this review, or following ongoing legal action that may potentially strike out the existing regulation altogether.Public health case: We believe that the partial ban applied to some forms of smokeless tobacco in the EU should be replaced by regulation of the toxicity of all smokeless tobacco. We hold this view for public health reasons: smokeless tobacco is substantially less harmful than smoking and evidence from Sweden suggests it is used as a substitute for smoking and for smoking cessation. To the extent there is a "gateway" it appears not to lead to smoking, but away from it and is an important reason why Sweden has the lowest rates of tobacco related disease in Europe. We think it is wrong to deny other Europeans this option for risk reduction and that the current ban violates rights of smokers to control their own risks. For smokers that are addicted to nicotine and cannot or will not stop, it is important that they can take advantage of much less hazardous forms of nicotine and tobacco-the alternative being to "quit or die"... and many die. While nicotine replacement therapies (NRT) may have a role in harm reduction, tobacco based harm reduction options may reach more smokers and in a different, market based, way. Chewing tobacco is not banned or regulated in the EU but is often highly toxic, and our proposal could remove more products from the market than it permitted.Regulatory options: We believe that the EU policy on smokeless tobacco should adapt to new scientific knowledge and that the European Commission should bring forward proposals to amend or replace Article 8 of directive 2001/37/EC with a new regulatory framework. Canada has developed testing regimens for tobacco constituents and these could be readily adapted to the European situation. A review of EU policy in this area is required no later than December 2004, and we believe the Commission should expedite the part of its review that deals with harm reduction and regulation of tobacco products other than cigarettes so as to reconsider its policy on smokeless tobacco. We held this view before Swedish Match brought its legal proceedings to challenge EU legislation and we will continue to hold these views if its action fails.

Bretteville-Jensen AL. To legalize or not to legalize? Economic approaches to the decriminalization of drugs. Substance Use & Misuse 41(4): 555-565, 2006. (32 refs.)

Drug legalization is gaining ever-widening support in most Western societies. A liberalization of current drug laws will most probably lead to a fall in drug prices. The present article focuses on recent economic studies examining the effects of a fall in prices on quantities consumed and recruitment. Estimates of price elasticities indicate that a substantial increase in consumption by current drug users should be expected if prices decrease, whereas estimates of participation elasticities suggest all increase in the number of users. Tests of the so-called gateway theory (i.e., whether the use of a less harmful drug increases the risk of future use of more harmful drugs) offers less unambiguous results.

Choo T; Roh S; Robinson M. Assessing the "gateway hypothesis" among middle and high school students in Tennessee. Journal of Drug Issues 38(2): 467-492, 2008. (61 refs.)

The current study examines the applicability of the "gateway hypothesis" to drug use patterns of secondary school students from a nonmetropolitan area in Tennessee. The data were collected from students in the 8(th), 10(th), and 12(th) grades at three secondary schools, using self-administered questionnaires under supervision of teachers. Although there is some support for the gateway hypothesis in our data, there is also evidence that what differentiates those who move from initial marijuana use to use of harder drugs are risk factors unique to individuals and their environments, consistent with the predictions of problem behavior theory and integrated systems theory. Implications for various interpretations of the gateway hypothesis are discussed.

Degenhardt L; Dierker L; Chiu WT; Medina-Mora ME; Neumark Y; Sampson N et al. Evaluating the drug use "gateway" theory using cross-national data: Consistency and associations of the order of initiation of drug use among participants in the WHO World Mental Health Surveys. Drug and Alcohol Dependence 108(1-2): 84-97, 2010. (32 refs.)

Background: It is unclear whether the normative sequence of drug use initiation, beginning with tobacco and alcohol, progressing to cannabis and then other illicit drugs, is due to causal effects of specific earlier drug use promoting progression, or to influences of other variables such as drug availability and attitudes. One way to investigate this is to see whether risk of later drug use in the sequence, conditional on use of drugs earlier in the sequence, changes according to time-space variation in use prevalence. We compared patterns and order of initiation of alcohol, tobacco, cannabis, and other illicit drug use across 17 countries with a wide range of drug use prevalence. Method: Analyses used data from World Health Organization (WHO) World Mental Health (WMH) Surveys, a series of parallel community epidemiological surveys using the same instruments and field procedures carried out in 17 countries throughout the world. Results: Initiation of "gateway" substances (i.e. alcohol, tobacco and cannabis) was differentially associated with subsequent onset of other illicit drug use based on background prevalence of gateway substance use. Cross-country differences in substance use prevalence also corresponded to differences in the likelihood of individuals reporting a non-normative sequence of substance initiation. Conclusion: These results suggest the "gateway" pattern at least partially reflects unmeasured common causes rather than causal effects of specific drugs on subsequent use of others. This implies that successful efforts to prevent use of specific "gateway" drugs may not in themselves lead to major reductions in the use of later drugs.

Ding K; Chang GA; Southerland R. Age of inhalant first time use and its association to the use of other drugs. Journal of Drug Education 39(3): 261-272, 2009. (24 refs.)

Inhalants are the 4th most commonly abused drugs after alcohol, tobacco, and marijuana. Although inhalants are often referred as Gateway Drugs this hypothesis is less examined. Using the 2003 National Survey on Drug Use and Health data, age of first time inhalant use was compared with the age of onset of other drugs among 6466 inhalant users who also used at least one of 14 other drugs. Findings indicated that only 4.2% multiple drug users who used inhalants prior to other drugs, especially alcohol, tobacco, and marijuana. Thus, the theory that inhalants are gateway drugs was not supported.

Ellgren M; Hurd YL; Franck J. Amphetamine effects on dopamine levels and behavior following cannabinoid exposure during adolescence. European Journal of Pharmacology 497(2): 205-213, 2004. (29 refs.)

The cannabis gateway hypothesis purports that early exposure to cannabis is a risk factor for subsequent use of other addictive drugs, e.g,, psychostimulants. Neurobiological sensitization, consistent with a gateway hypothesis, was currently studied in regard to amphetamine response. Rats were exposed to the cannabinoid receptor agonist WIN 55,212-2 [(R)-(+)-[2,3-dihydro-5-methyl-3-(4-morpholinylmethyl)pyrrolo[1,2,3-de]- 1,4-benzoxazin-6-yl]-1-naphthalenylmethanone] 1.25 mg/kg, intraperitoneally; i.p.) for 5 days during early adolescence. Amphetamine (0.5 mg/kg, i.p.) or WIN 55,212-2 (1.25 mg/kg, i.p.) was administered in late adolescence and in vivo dopamine levels were simultaneously measured in the nucleus accumbens. Locomotor and stereotyped behaviors were also monitored in rats pretreated with WIN 55,212-2 (0.625, 1.25 or 2.5 mg/kg) or Delta-9-tetrahydrocannabinol (0.75, 1.5 or 3.0 mg/kg, i.p.) for 5 days during early adolescence and challenged with amphetamine (0.5 or 2.0 mg/kg) in late adolescence or as adults. Pretreatment with WIN 55,212-2 or Delta-9-tetrahydrocannabinol during early adolescence did not alter the dopaminergic or behavioral responses to amphetamine in adolescence or adulthood. In conclusion, these findings do not support the cannabis gateway hypothesis in regard to subsequent amphetamine exposure.

Fagerstrom KO; Schildt E-B. Should the European Union lift the ban on snus? Evidence from the Swedish experience. Addiction 98(9): 1191-1197, 2003. (30 refs.)

The very low smoking prevalence in Sweden has received considerable attention. Sweden was the only country in Europe to reach the World Health Organizations' goal of less than 20%, daily smoking prevalence among adults by year 2000. Only 17% of Swedish men smoke. Some have argued that this has been achieved because Swedes use another form of tobacco instead. Sweden has a high level of use of a moist snuff product called 'snus'. Nineteen per cent of adult men and 1%, of women are daily users and the trend is increasing. Epidemiological studies have failed to find evidence that snus causes cancers, including oral cancer. Its adverse effects on the cardiovascular system are debated, but are certainly less than those of smoking. Recent studies among former smokers indicate that many men have quit smoking using snus. Forty-seven per cent of current snus users are former smokers and 28% of ex-smoking used snus at their last attempt to stop smoking. The association between high snus consumption and low smoking prevalence has been debated and challenged. It has been argued that snus may be a gateway to cigarette smoking. Recent data has found that among those starting tobacco use in the form of snus, 20% later go on to smoking while the same risk for those not starting with snus is 43%. On balance, there is reason to believe that having snus available to the Swedish population has been of benefit to public health. Repealing the ban on snus in the rest of the European Union might also have some positive effect, depending on the marketing.

Fergusson DM; Boden JM; Horwood LJ. Cannabis use and other illicit drug use: Testing the cannabis gateway hypothesis. Addiction 101(4): 556-569, 2006. (67 refs.)

Aim: To examine the associations between the frequency of cannabis use and the use of other illicit drugs. Design: A 25-year longitudinal study of the health, development and adjustment of a birth cohort of 1265 New Zealand children. Measurements: Annual assessments of the frequency of cannabis use were obtained for the period 14-25 years, together with measures of the use of other illicit drugs from the same time period. Findings: The frequency of cannabis use was associated significantly with the use of other illicit drugs, other illicit drug abuse/dependence and the use of a diversity of other drugs. This association was found to be particularly strong during adolescence but declined rapidly as age increased. Statistical control for confounding by both fixed and time dynamic factors using random- and fixed-effects regression models reduced the strength of association between frequency of cannabis use and other illicit drug use, but a strong association between frequency of cannabis use and other illicit drug use remained even after control for non-observed and time-dynamic sources of confounding. Conclusions: Regular or heavy cannabis use was associated with an increased risk of using other illicit drugs, abusing or becoming dependent upon other illicit drugs, and using a wider variety of other illicit drugs. The risks of use, abuse/dependence, and use of a diversity of other drugs declined with increasing age. The findings may support a general causal model such as the cannabis gateway hypothesis, but the actual causal mechanisms underlying such a gateway, and the extent to which these causal mechanisms are direct or indirect, remain unclear.

Fergusson DM; Boden JM; Horwood LJ. Testing the cannabis gateway hypothesis: Replies to Hall, Kandel et al. and Maccoun (2006) (editorial). Addiction 101(4): 474-476, 2006. (6 refs.)

Furr-Holden CDM; Ialongo NS; Anthony JC; Petras H; Kellam SG. Developmentally inspired drug prevention: Middle school outcomes in a school-based randomized prevention trial. Drug and Alcohol Dependence 73(2): 149-158, 2004. (39 refs.)

Prior investigations have linked behavioral competencies in primary school to a reduced risk of later drug involvement. In this randomized prevention trial, we sought to quantify the potential early impact of two developmentally inspired universal preventive interventions on the risk of early-onset alcohol, inhalant, tobacco, and illegal drug use through early adolescence. Participants were recruited as they entered first grade within nine schools of an urban public school system. Approximately, 80% of the sample was followed from first to eighth grades. Two theory-based preventive interventions, (1) a family-school partnership (FSP) intervention and (2) a classroom-centered (CC) intervention, were developed to improve early risk behaviors in primary school. Generalized estimating equations (GEE) multivariate response profile regressions were used to estimate the relative profiles of drug involvement for intervention youths versus controls, i.e. youth in the standard educational setting. Relative to control youths, intervention youths were less likely to use tobacco, with modestly stronger evidence of protection associated with the CC intervention (RR = 0.5; P = 0.008) as compared to protection associated with the FSP intervention (RR = 0.6; P = 0.042). Intervention status was not associated with risk of starting alcohol, inhalants, or marijuana use, but assignment to the CC intervention was associated with reduced risk of starting to use other illegal drugs by early adolescence, i.e. heroin, crack, and cocaine powder (RR = 0.32, P = 0.042). This study adds new evidence on intervention-associated reduced risk of starting illegal drug use. In the context of 'gateway' models, the null evidence on marijuana is intriguing and merits attention in future investigations.

Galanti MR; Rosendahl I; Wickholm S. The development of tobacco use in adolescence among "snus starters" and "cigarette starters": An analysis of the Swedish "BROMS" cohort. Nicotine & Tobacco Research 10(2): 315-323, 2008. (41 refs.)

Whether the use of smokeless tobacco can facilitate the transition to cigarette smoking and/or to prolonged tobacco use in adolescence is unclear. We analyzed data from a cohort of 2,938 Swedish adolescents, with six follow-up assessments of tobacco use between the ages of 11 and 18 years. The majority of tobacco users (70%) started by smoking cigarettes, 11% took up snus before smoking, and 19% used both tobacco types close in time. Ever users of tobacco at baseline had a higher risk of being current smokers and/or smokeless tobacco users at the end of follow-up compared with never users, with the highest excess relative risk for "mixed users." Adolescents who initiated tobacco use with cigarettes had a non-significantly increased probability to end up as current smokers compared with snus starters (adjusted OR=1.42; 95% CI 0.98-2.10) The OR of smoking for "mixed starters" was 2.54 (95% CI 1.68-3.91). The risk of becoming current user of any tobacco was also significantly enhanced for "mixed starters." Marked sex differences were observed in these associations, as initiation with cigarettes rather than with snus predicted current smoking or tobacco use only among females. Progression of tobacco use in adolescence is not predicted by onset with snus or cigarettes, but rather by initiation with both tobacco types close in time and/or at young age. The proportion of adolescent smoking prevalence attributable to a potential induction effect of snus is likely small.

George S; Moselhy H. "Gateway hypothesis" -- a preliminary evaluation of variables predicting non-conformity. (letter). Addictive Disorders and Their Treatment 4(1): 39-40, 2005. (4 refs.)

This letter reports the results of an exploratory study to explore the "gateway hypothesis", specifically whether there are patient variables that discriminate those whose who follow the "gateway" -- i.e. their use of licit drugs, i.e. alcohol, nicotine, leads to the use of illicit drugs -- from those for whom this is not the case. Two groups were identified those, those whose drug use progressed from "soft" drugs to hard drugs or whether they started using "hard" drugs (a reversed gateway.) The first group (typical ''gateway'') had the following characteristics: 72 (68.8%) were male and 34 (31.2%) were female; 69 (65%) were whites and 20 (19%) were Pakistani; 57 (54%) were single; 87 (82%) were unemployed; 28 (26%) had a mental health consultation in the last 2 years; 57 (54%) had a family history of drug dependence, and the age of first presentation to drug treatment services was 25.1(66.9) years. The "reversed gateway" group had the following characteristics: 27 (79%) were male and 7 (21%) were female; 18 (54%) were white and 9 (26%) were Pakistani; 21(62%) were unemployed; 12 (34%) had a mental health consultation in the last 2 years; 21(62%) had a family history of drug dependence and the age of first presentationfto drug treatment services was 23.2 years. There were no statistically significant differences between the 2 groups on any of these variables.

George S; Moselhy H. Patterns and pathways of substance use in patients attending a community drug team. Addictive Disorders and Their Treatment 2(4): 151-156, 2003. (8 refs.)

Our primary aim was to describe the patterns of drug use and its consequences in a group of patients attending a Community Drug Team (CDT) in East Birmingham--"Azaadi." We also attempted to trace their sequence of progression to "hard" drug use. This was a retrospective, case-record based analysis of drug misusers attending "Azaadi." One hundred and forty case-records were reviewed by a psychiatrist (S.G.) and the relevant information was extracted using a pre-designed data sheet, which was later analyzed. Ninety-nine Ss were male (71%); 41 were female (29%), 70 were Caucasian (71%), and 82 were single (58%). Seventy-nine percent of the sample were heroin users, 32% had mental health problems, and 55% had a positive family history of drug abuse. Alcohol, cannabis and glue were the substances first misused by these patients, and then they progressed to use of "hard" drugs like heroin and cocaine, with some differences between ethnic groups. This descriptive study describes the patient characteristics and associated features of drug misusers registered with a CDT. Results indicate the high rates of psychosocial morbidity and the sequence of progression from "soft" drug use to "hard" drug use, which is in support of the "gateway effect."

Ginzler JA; Cochran BN; Domenech-Rodraguez M; Cauce AM; Whitbeck LB. Sequential progression of substance use among homeless youth: An empirical investigation of the gateway theory. Substance Use & Misuse 38(3/6): 725-758, 2003. (41 refs.)

We examined the sequence of substance-use initiation in 375 street youth (age 13-21) who were interviewed from 1994-99 in Seattle, Washington. Based on the "gateway theory," participants were categorized into six profiles to describe the order in which they initiated use of various substances (i.e., alcohol, marijuana, other drugs), or classified as nonprogressors if they had not tried all three classes of drugs. Youth progressing in the hypothesized gateway order (i.e., alcohol preceding marijuana, followed by other drugs) initiated their use at an earlier age than youth who had not progressed through all three substance classes. However, there was no relationship between a substance initiation profile and current substance-use. Implications include the recognition that street youth may follow different patterns of use than normative groups, and that interventions geared toward youth who use substances heavily must include contextual factors, in addition to substance-use history.

Golub A; Johnson BD; Dunlap E. Subcultural evolution and illicit drug use. Addiction Research & Theory 13(3): 217-229, 2005. (84 refs.)

This article articulates a subcultural basis to the evolving popularity for different illicit drugs primarily based on empirical research in the United States, especially among inner-city populations. From this perspective, drug use emerges from a dialectic between drug subcultures with individual identity development. The prevailing culture and subcultures affect drugs' popularity by imparting significance to their use. Innovations, historical events, and individual choices can cause subcultures to emerge and change over time. This subcultural view provides insight into the widespread use of licit drug, the dynamics of drug eras (or epidemics), the formation of drug generations, and the apparent "gateway" phenomenon.

Grau LE; Dasgupta N; Harvey AP; Irwin K; Givens A; Kinzly ML; Heimer R. Illicit use of opioids: Is OxyContin (R) a "Gateway drug''? American Journal on Addictions 16(3): 166-173, 2007. (42 refs.)

This study examines whether individuals who engage in illicit, non-medical use of OxyContin((R)) are distinguishable from other non-medical users of opioids and whether OxyContin serves as a "gateway'' to heroin and/or injection drug use. The study sample included active non-medical users of opioids, who are 16 years or older and residents of Cumberland County, Maine. Possible associations between type of opioid used and behavioral and descriptive variables were assessed. The study sample was predominantly urban-dwelling, male, Caucasian, and economically disadvantaged. OxyContin users could only be distinguished from heroin users (non-heroin opioid users). Polyopioid use within the first year of initiation was associated with quicker progression to heroin and injection drug use.

Hall W. Dissecting the causal anatomy of the link between cannabis and other illicit drugs. (editorial). Addiction 101(4): 472-473, 2006. (8 refs.)

Hall W; Pacula RL. Cannabis Use and Dependence: Public Health and Public Policy. Melbourne: Cambridge University Press, 2003. (960 refs.)

The use of cannabis in the late twentieth and this century is an area of medical and moral controversy. Despite its illegality, cannabis is the most widely used drug after alcohol and tobacco among young adults in Australia, the USA and Europe. This book explores the relationship between health policy, public health and the law regarding cannabis use. The book is organized into 8 sections. The first section describes cannabis as a drug and the ways in which it is typically used. Section 2 (chapters 3-5) reviews the evidence of adverse health effects associated with cannabis use including acute effects, chronic effects on cellular, immunological, and reproductive functioning, and cardiovascular, respiratory and gastrointestinal system. Section 3 (Chapters 7-9) examines the psychological effects of chronic use. These include effects on motivation and the risk of dependence, effects on cognitive function and risk of developing psychosis. The fourth section (chapters 10-11) deals with the most contentious issues in the debate on cannabis, effects on adolescents. The gateway hypothesis is reviewed as well as the effects of cannabis on psychosocial outcomes of adolescence. The fifth sections (chapters 11-12) considers the harms and benefits of cannabis use, the latter which are generally not considered. Section six discusses the cannabis policy debate, This includes two central claims of strategic significance to the case for legal reform, whether prohibition has any deterrent effects and the economic costs of enforcing the current prohibitions. There is also a summary of some of the tangible costs of cannabis prohibition that have been identified by its critics, including the loss of liberty to use marijuana, the creation of a black market, disrespect for a widely broken and minimally enforced law, harm to users' reputations, impaired health education about marijuana and other drugs, the loss of benefits from marijuana including medical use, and the inefficient use of law enforcement resources. Section seven explores, in detail, alternative cannabis policy. There is a discussion of variations of prohibition that have been proposed and trialled in a number of countries. There is also discussion of the possibility for a legal market in which cannabis could be legally produced, sold and used. The nature of a heavily regulated legal cannabis market is set forth. The final chapter summarizes the arguments that have been put forth about the harms of cannabis use and the costs and effectiveness of prohibition. The authors argue that marijuana policies need to be more responsive to evidence on both the adverse health effects of marijuana and the costs and effectiveness of marijuana control policies. The do suggest ways to move the policy debate forward by developing support for incremental policy changes - the costs and effects of which could be systematically evaluated.

Hall W; Solowij N. The adverse health and psychological consequences of cannabis dependence. IN: Roffman RA; Stephens RS, eds. Cannabis Dependence: Its Nature, Consequences and Treatment. London: Cambridge University Press, 2006. pp. 106-132

This chapter considers morbidity associated with chronic marijuana use. Among the conidtions addressed are the respiratory risks of smoking marijuana, respiratory cancers associated with long term use, brain function and cognitivie impairment associated with chronic use, and the role of cannabis in accidental injury. The cardiovascular effects of cannabis use are reviewed. In addition psychological/behavioral related effects are addressed, such as the impact of different levels of marijuana use on school performance,the relationsip of cannabis use ato psychosis and schizophrenia, and the "gateway hypothesis", as well as special populations of cannabis-dependent persons.

Hall WD; Lynskey M. Is cannabis a gateway drug? Testing hypotheses about the relationship between cannabis use and the use of other illicit drugs. (review). Drug and Alcohol Review 24(1): 39-48, 2005. (66 refs.)

We outline and evaluate competing explanations of three relationships that have consistently been found between cannabis use and the use of other illicit drugs, namely, (1) that cannabis use typically precedes the use of other illicit drugs; and that (2) the earlier cannabis is used, and (3) the more regularly it is used, the more likely a young person is to use other illicit drugs. We consider three major competing explanations of these patterns: (1) that the relationship is due to the fact that there is a shared illicit market for cannabis and other drugs which makes it more likely that other illicit drugs will be used if cannabis is used; (2) that they are explained by the characteristics of those who use cannabis; and (3) that they reflect a causal relationship in which the pharmacological effects of cannabis on brain function increase the likelihood of using other illicit drugs. These explanations are evaluated in the light of evidence from longitudinal epidemiological studies, simulation studies, discordant twin studies and animal studies. The available evidence indicates that the association reflects in part but is not wholly explained by: (1) the selective recruitment to heavy cannabis use of persons with pre-existing traits (that may be in part genetic) that predispose to the use of a variety of different drugs; (2) the affiliation of cannabis users with drug using peers in settings that provide more opportunities to use other illicit drugs at an earlier age; (3) supported by socialisation into an illicit drug subculture with favourable attitudes towards the use of other illicit drugs. Animal studies have raised the possibility that regular cannabis use may have pharmacological effects on brain function that increase the likelihood of using other drugs. We conclude with suggestions for the type of research studies that will enable a decision to be made about the relative contributions that social context, individual characteristics, and drug effects make to the relationship between cannabis use and the use of other drugs.

Humfleet GL; Haas AL. Is marijuana use becoming a 'gateway' to nicotine dependence? (editorial). Addiction 99(1): 5, 2004. (8 refs.)

Previous studies have documented a reliable pattern for initiating substance use, with many adolescents beginning with nicotine and/or alcohol and progressing to illicit drugs. Nicotine is a particularly potent gateway drug for marijuana. However, recent research suggests that a 'reverse gateway' effect may occur for some cigarette smokers, with marijuana use preceding tobacco. In this issue, Amos et al. report on a qualitative study examining the relationships between tobacco and marijuana use among adolescents and young adults in Scotland. A fundamental theme in this report is the link between cannabis use and cigarette smoking, and how this association reinforced nicotine use in general. Combined use of tobacco and marijuana is a cross-cultural phenomenon. In the United States concurrent use of cigarettes and marijuana is common, as is the use of blunts, marijuana rolled in cigar papers. Studies highlight the universality of this problem in adolescents and introduce another layer of complexity to drug prevention and nicotine cessation efforts.

Kanayama G; Cohane GH; Weiss RD; Pope HG. Past anabolic-androgenic steroid use among men admitted for substance abuse treatment: An under-recognized problem? Journal of Clinical Psychiatry 64(2): 156-160, 2003. (64 refs.)

Background: Recent reports suggest that anabolic-androgenic steroids (AAS) may cause mood disorders or dependence syndromes and may help to introduce some individuals to opioid abuse. At present, however, little is known about prior AAS use among men entering inpatient substance abuse treatment. Method: We assessed lifetime AAS use in 223 male substance abusers admitted to a substance abuse treatment unit primarily for treatment of alcohol, cocaine, and opioid dependence. Subjects reporting definite or possible AAS use were then asked to participate in a detailed semi-structured interview that covered demographics, drug use history, and symptoms experienced during AAS use and withdrawal, and whether AAS use had helped introduce the subject to other classes of drugs. Results: Twenty-nine men (13%) reported prior AAS use, but this history was documented on physicians' admission evaluations in only 4 cases. Among 88 men listing opioids as their drug of choice, 22 (25%) acknowledged AAS use, versus only 7 (5%) of the other 135 men (p < .001). Twenty-four (83%) of the 29 AAS users were interviewed in detail. Seven (29%) of the men interviewed, all with opioid dependence, reported that they first learned about opioids from friends at the gym and subsequently first obtained opioids from the same person who had sold them AAS. Eighteen (75%) of the men interviewed 7 reported that AAS were the first drugs that they had ever self-administered by injection, 4 (17%) reported severe aggressiveness or violence during AAS use, 1 (4%) attempted suicide during AAS withdrawal, and 5 (21%) described a history of AAS dependence. Conclusion: Prior AAS use appears to be common but underrecognized among men entering inpatient substance abuse treatment, especially those with opioid dependence. AAS use may serve as a "gateway" to opioid abuse in some cases and may also cause morbidity in its own right.

Kandel DB. Does marijuana use cause the use of other drugs? (editorial). Journal of the American Medical Association 289(4): 482-483, 2003. (9 refs.)

A developmental sequence of involvement in drugs is one of the best replicated findings in the epidemiology of drug use. Regular sequences and stages of progression in which the use of alcohol and cigarettes precedes the use of marijuana (cannabis), and, in turn, the use of marijuana precedes the use of other illicit drugs, has been observed in the United States as well as in other western societies.1 Very few individuals who have tried cocaine and heroin have not already used marijuana; the majority have previously used alcohol or tobacco. Such behavioral regularities are subsumed under the "gateway hypothesis." The gateway hypothesis implies interrelated propositions about sequencing, association of initiation, and causation. Whether or not a true causal link exists between the use of marijuana and other drugs, the association between the 2 has been well established. It is important, however, to appreciate that the progression is not inevitable. Not all those who try marijuana will subsequently use cocaine or become heroin addicts.

Kandel DB; Yamaguchi K; Klein LC. Testing the gateway hypothesis. (editorial). Addiction 101(4): 470-472, 2006. (11 refs.)

Kikuchi A; Wada K. Factors associated with volatile solvent use among junior high school students in Kanto, Japan. Addiction 98(6): 771-784, 2003. (37 refs.)

Aims To estimate the relative association between life-time volatile solvent use and risk factors for usage. Design Cross-sectional anonymous questionnaire survey. Setting junior high schools in Kanto, Japan. Participants junior high school students (n = 7 744). Measurements Data on life-time and past-year solvent use, demographic variables, urbanization, regularity of waking patterns, school life, family life, peer relationships, prior alcohol and cigarette use and knowledge on harmful effects of solvent use. Findings Uni- and multivariate logistic regression analyses were conducted to estimate crude and adjusted odds ratios for each index. The primary findings were (1) 'smoking cigarettes nearly every day' (adjusted OR=9.88, 95% Cl = 3.74, 26.12) and peer pressure measured by 'been tempted to use solvents' (adjusted OR = 9.53, 95% Cl = 4.84, 18.74) demonstrated the highest adjusted odds ratios; (2) being male (adjusted OR = 2.56, 95% Cl = 1.3 7, 4.76), seeing school life as 'not at all enjoyable' (adjusted OR = 2.69, 95% CI = 1.03, 7.01) and family environment as 'neither good nor bad' (adjusted OR = 2.15, 9 5% CI = 1.19, 3.88) also showed significant association; (3) life-time alcohol use did not show a significant association in the multivariate model (adjusted OR = 0.80, 95% Cl = 0.30, 2.12); and (4) solvent use appeared independent of knowledge regarding its effects ('death by acute intoxication', 'psychotic symptoms','amotivational syndrome', 'flashbacks' adjusted ORs all non-significant). Conclusion Alcohol use may not function as a gateway to solvent use in Japan. The reasons may be culture-bound. A longitudinal study is required to test this hypothesis.

Klanecky AK; Salvi S; McChargue DE. Coerced childhood sexual abuse moderates the association between cigarette smoking initiation and college drug use frequency. American Journal on Addictions 18(5): 363-366, 2009. (30 refs.)

The current study examined childhood sexual abuse (CSA) as a potential moderator of the "gateway theory" association of cigarette use onset and college drug use. Covariate adjusted hierarchical regressions showed that CSA history interacted with age of first cigarette to predict total 12-month illicit drug use frequency (Delta R-2 = .048, F(10, 76) = 4.041, Mse = 8.812, p = .021). Simple effects revealed that age of first cigarette predicted drug use frequency in individuals with CSA histories (p = .045) rather than non-CSA individuals (p = .103). Exploratory analyses further revealed that the CSA moderation was carried primarily by those exposed to forced/coerced CSA events. Implications of the findings are discussed.

Kozlowski LT; O'Connor RJ; Edwards BQ; Flaherty BP. Most smokeless tobacco use is not a causal gateway to cigarettes: Using order of product use to evaluate causation in a national US sample. Addiction 98(8): 1007-1085, 2003. (34 refs.)

Aims To evaluate non-causal and causal patterns of smokeless tobacco (SIT) and cigarette use; to assess the prevalence of 'non-gateway' and possible 'gateway patterns of SIT use. Design and setting Data from the Cancer Control Supplement to the 19 8 7 National Health Interview Survey, a representative survey of non-institutionalized adults in the United States. From reported age at first use, participants were categorized by type and sequence of tobacco product use. SUDAAN 8.0.1 was used for statistical analyses. Participants Males aged 18-34 (n=3454), weighted to provide estimates of the US population. A subsample of males aged 23-34 (n=2614) was analyzed to minimize the possibility of future product switching. Measurements Smoking status, smokeless tobacco (snuff, chewing tobacco, both) use status, age at regular use of cigarettes, age at first use of smokeless tobacco. Findings Of those 23-34-year-olds who had ever used SLT with or without cigarettes. 77.2% (95%, CI: 71.3, 83.3) were classifiable as non-gateway users in that 35.0% (95% CI: 29.9, 40.1) had only used SIX and 42.2% (95%, CI: 36.8, 47.7) had used cigarettes first. Cigarette use in younger cohorts was less common, despite increased SLT use. Those who used cigarettes before moist snuff were 2.1 times more likely to have quit smoking (95% CI 1.21,6.39) than cigarette-only users. Conclusions The large majority of SLT users are non-gateway users. Causal gateway effects should be of minor concern for policy. SLT may be more likely to prevent smoking than cause it.

Kozlowski LT; O'Connor RJ; Edwards BQ; Flaherty BP. Most smokeless tobacco use is not a causal gateway to cigarettes. Response to Tomar and Lorree (2004). (letter). Addiction 99(2): 262-263, 2004. (2 refs.)

This is a response to a letter commenting on the authors article published in this volume, 98(8).

Lee D. Residential mobility and gateway drug use among hispanic adolescents in the US: Evidence from a national survey. American Journal of Drug and Alcohol Abuse 33(6): 799-806, 2007. (22 refs.)

Residential mobility has been an important topic in public health for the past decades. More than 22 million Americans migrated from state to state in 2000, but characteristics of minority American movers are not well documented in the aspect of public health. Using the U. S. national survey, we examined the association between residential mobility and gateway drug use among Hispanic adolescents in the U. S. Frequent movers and never movers were compared in the study. The study results indicate that frequent movers ( moved more than 4 times for the past 5 years) were more likely than never movers to smoke and use marijuana. We also found that frequent residential relocation, females, and older teenagers (14-17) are risk factors of gateway drug use among Hispanic adolescents.

Levine SB; Coupey SM. Nonmedical use of prescription medications: An emerging risk behavior among rural adolescents. Journal of Adolescent Health 44(4): 407-409, 2009. (10 refs.)

Little is known about prescription medication abuse by rural youth. We surveyed 849 rural high school students and found that 34% reported lifetime nonmedical use of prescription medication higher than the 12% reported nationally. Boys and marijuana users had higher odds of nonmedical use of prescription medication than did girls or marijuana nonusers (odds ratio 1.9 and 3.8, respectively).

Levine SB; Coupey SM. Nonmedical use of prescription medications: An emerging risk behavior among rural adolescents. Journal of Adolescent Health 44(4): 407-409, 2009. (10 refs.)

Luna N. Facts about drugs. IN: Hogan J; Gabrielsen K; Luna N; Grothaus, eds. Substance Abuse Prevention: The Intersection of Science and Practice. New York: Allyn & Bacon, 2003. pp. 68-102. (28 refs.)

This chapter offers a discussion of different models of addiction and then reviews the major drug classes: depressants; opiates; stimulants; hallucinogens; cannabinols; steroids; and inhalants. For each of these the is a review of the drug effects, symptoms of overdose, posible withdrawal syndrome; and both acute and chronic effects. The chapter concludes with consideration of "gateway" drugs, and data on trends of drug use.

Lynskey MT; Vink J; Boomsma D. Early onset cannabis use and progression to other drug use in a sample of Dutch twins. Behavior Genetics 36(2): 195-200, 2006. (32 refs.)

One possible explanation of the commonly reported associations between early onset cannabis use and elevated risks of other illicit drug use is that early onset cannabis use increases access and availability to other drugs. It was this argument that in part motivated policy changes in the Netherlands that led to the de facto legalization of cannabis there. This study examines, using a co-twin control design, whether previously observed associations between early onset cannabis use and elevated lifetime rates of other illicit drug use would also be observed in a sample of 219 same sex Dutch twin pairs discordant for cannabis use before age 18. After adjustment for covariates, rates of lifetime party drug use (OR=7.4, 95% CI=2.3-23.4), hard drug use (OR=16.5, 95% CI=2.4-111.3), but not regular cannabis use (OR=1.3, 95% CI=0.3-5.1) were significantly elevated in individuals who reported early onset cannabis use, relative to their co-twin who had not used cannabis by age 18. The elevated odds of subsequent illicit drug use in early cannabis users relative to their non early using co-twins suggests that this association could not be explained by common familial risk factors, either genetic or environmental, for which our co-twin methodology provided rigorous control.

Maccoun RJ. Competing accounts of the gateway effect: The field thins, but still no clear winner. (editorial). Addiction 101(4): 473-474, 2006. (12 refs.)

Makanjuola VA; Oladeji BD; Gureje O. The gateway hypothesis of substance abuse: An examination of its applicability in the Nigerian general population. Substance Use & Misuse 45(10): 1558-1571, 2010. (28 refs.)

The study aims to estimate the prevalence and predictors of not following the gateway theory. Respondents were selected from a multistage stratified clustered sampling of households in five of Nigeria's six geopolitical regions. Interviews were conducted between February 2002 and May 2003 using the CIDI-version. 3 with a total sample size (N) of 2,143. Cumulative incidence proportions of not following a gateway pattern were estimated with SUDAAN. Predictors of this were estimated using multivariate logistic regression models. The deviation from the normative sequence of drug use occurs albeit infrequently. The public health implications of this are discussed as well as the limitations of the findings.

Mayet A; Legleye S; Chau N; Falissard B. The mediation role of licit drugs in the influence of socializing on cannabis use among adolescents: A quantitative approach. Addictive Behaviors 35(10): 890-895, 2010. (48 refs.)

Licit substance use could be an early stage leading on to cannabis use. The aim of the study was to test a hypothetical sequential process leading from socializing to cannabis use so as to evaluate the mediator role of tobacco and alcohol. Data was derived from a French nationwide survey carried out in 2005 involving 29,393 teenagers aged 17. The analysis used structural equation modelling. The sequence tested was: socializing with friends-tobacco/alcohol use-cannabis use-cannabis use disorders (CUD). Tobacco and alcohol consumptions appeared to be similarly influenced by the time spent with friends. However, tobacco mediation explained 57% of the sequence leading to cannabis use and 61% of the sequence leading to CUD, while the role of alcohol was weaker, at around 13%. Our results underline the effect of peer influence, in the course of night-out socializing, on substance use among adolescents, and the importance of tobacco mediation in the process leading to cannabis use and misuse. This suggests that prevention in places frequented by adolescents should primarily target tobacco consumption, which explains the largest part of cannabis use variance. However, processes linking substance uses seem to be more complex, with the existence of reverse pathways from cannabis to licit drugs. Thus, the gateway effects of tobacco and alcohol require further exploration in relation to simultaneous polysubstance use.

Melberg HO; Jones AM; Bretteville-Jensen AL. Is cannabis a gateway to hard drugs? Empirical Economics 38(3): 583-603, 2010. (25 refs.)

The gateway hypothesis proposes that use of cannabis directly increases the risk of consuming hard drugs. We test this controversial, but influential, hypothesis on a sample of cannabis users, exploiting a unique set of drug price data. A flexible approach is developed to identify the causal gateway effect using a bivariate survival model with shared frailty estimated using a latent class approach. The model suggests two distinct groups; a smaller group of "troubled youths" for whom there is a statistically significant gateway effect that more than doubles the hazard of starting to use hard drugs and a larger fraction of youths for whom previous cannabis use has less impact.

Menendez RG. Chemical addiction experiences in Havana's Psychiatric Hospital. Addictive Disorders and Their Treatment 4(4): 139-144, 2005. (26 refs.)

To describe our experiences in the treatment of alcoholism and other addictions that affect behavior, the author addresses the significance of drugs within a system integrated by legal prescription and illegal misuse of substances, which also has important reciprocal potentialities of induction and reinforcement; thus, attention should begin with the prevention of legal drug use and misuse. This article is based on a 25-year working period in a unit at the Havana Psychiatric Hospital for the Rehabilitation of Cuban and Foreigner Alcoholics and Other Drug Addicts, an institution appointed as a National Reference Center in this subject. It comprises national criteria about anti-alcoholic and other drug programs where alcohol is considered both as a paradigmatic and as a gateway drug. A conceptual framework, basic principles, and organizing standards, as well as programmatic methods and resources used in Cuba, are discussed. The high requirement of spirituality, ethics, and humanism in this program is also stressed.

Montoya ID; Atkinson J; McFaden WC. Best characteristics of adolescent gateway drug prevention programs. Journal of Addictions Nursing 14(2): 75-83, 2003. (81 refs.)

This paper identifies the best characteristics of gateway drug prevention programs that have the effect of preventing or reducing the use of alcohol, tobacco, and marijuana by adolescents. A comprehensive literature review of the performance of school-, family-, and community-based drug prevention programs covering the last 20 years was conducted to identify the best characteristics of successful programs. Six characteristics were identified that are common to successful drug prevention programs: involving parents; teaching life and resistance skills and normative education; enacting laws and policies against adolescent drug use; encouraging peer participation; conducting a media campaign; and retaining program participants. School administrators, parents, and community leaders can use the knowledge in this paper to design drug prevention programs that can accommodate specific risk factors and types of gateway drug use by adolescents.

O'Connor RJ; Flaherty BP; Edwards BQ; Kozlowski LT. Regular smokeless tobacco use is not a reliable predictor of smoking onset when psychosocial predictors are included in the model. Nicotine & Tobacco Research 5(4): 535-543, 2003. (28 refs.)

Tomar (Nicotine & Tobacco Research, 5, 545-553) analyzed the CDC's Teenage Attitudes and Practices Survey (TAPS) and reported smokeless tobacco may act as a starter product for or gateway to cigarettes. Regular smokeless tobacco users at baseline were said to be 3.45 times more likely than never users of smokeless tobacco to become cigarette smokers after 4 years (95% CI = 1.84-6.47). However, this analysis did not take into account well-known psychosocial predictors of smoking initiation. We reanalyzed TAPS to assess whether including psychosocial predictors of smoking affected the smokeless tobacco gateway effect. Experimenting with smoking, OR = 2.09 (95% CI = 1.51-2.90); below average school performance, OR = 9.32 (95% CI = 4.18-20.77); household members smoking, OR = 1.49 (95% CI = 1.13-1.95); frequent depressive symptoms, OR = 2.19 (95% CI = 1.25-3.84); fighting, OR = 1.48 (95% CI = 1.08-2.03); and motorcycle riding, OR = 1.42 (95% CI = 1.06-1.91) diminished the effect of both regular, OR = 1.68 (95% CI = .83-3.41), and never regular smokeless tobacco use, OR = 1.41 (95% CI = .96-2.05), to be statistically unreliable. Analyzing results from a sample of true never smokers (never a single puff) showed a similar pattern of results. Our results indicate that complex multivariate models are needed to evaluate recruitment to smoking and single factors that are important in that process. Tomar's analysis should not be used as reliable evidence that smokeless tobacco may be a starter product for cigarettes.

Plancherel B; Bolognini M; Stephan P; Laget J; Chinet L; Bernard M et al. Adolescents' beliefs about marijuana use: A comparison of regular users, past users and never/occasional users. Journal of Drug Education 35(2): 131-146, 2005. (32 refs.)

A questionnaire investigating adolescents' opinions and experiences regarding marijuana use was administered to 163 adolescents and young adults (96 boys and 67 girls) aged 13 to 20 (mean age = 16.8, s.d. = 1.5). Items referred to marijuana and other substances' dangerousness, representations regarding the positive and negative consequences of marijuana use. Responses were compared according to marijuana use status (classified into never/occasional use, current regular use and past regular use). Results show that adolescents' opinions differ according to their experience with marijuana use. Current regular users evaluate marijuana as less dangerous, but alcohol and heroin as more dangerous in comparison with never/occasional and past users. Current and past users are more likely to define marijuana as a medical drug and a plant used in agriculture, and less likely to define it as an illegal drug. Current and past users evaluate marijuana use as a way to cope with stress, to relax to a greater extent than do never/occasional users do. The latter attribute more negative consequences to marijuana use such as diminished driving ability and school performance and a pathway to hard drugs.

Rebellon CJ; Van Gundy K. Can social psychological delinquency theory explain the link between marijuana and other illicit drug use? A longitudinal analysis of the gateway hypothesis. Journal of Drug Issues 36(3): 387-411, 2006. (44 refs.)

Extensive research suggests that marijuana use tends to precede the use of other illicit substances among adolescents. At the same time, there remain two viable interpretations of such research. First, marijuana use may cause an increase in one's probability of using other drugs. Second, the correlation between marijuana use and other drug use may be spurious, reflecting the influence of one or more "third variables" that simultaneously cause both behaviors. The present paper provides an empirical assessment of each view using panel data from three waves of the National Youth Survey. Even after adjusting for the influence of variables derived from strain theory,use patterns/ social bonding theory and differential association theory a series of longitudinal logistic regression analyses fail to disconfirm the hypothesis that marijuana use exerts a causal influence on one's probability of using other illicit substances. A three-wave panel model adjusting for the influence of unmeasured variables yields similar results.

Reich MS; Dietrich MS; Martin PR. Temporal sequence of incident cigarette, coffee, and alcohol use among AA participants. (review). American Journal of Drug and Alcohol Abuse 37(1): 27-36, 2011. (48 refs.)

Background: Cigarettes and coffee are widely used psychoactive substances among alcoholics. Due to the devastating public health impact of alcohol use disorders, it is important to determine if using cigarettes or coffee may influence alcoholism. Previous studies indicate that cigarette smoking is associated with progression of alcohol dependence, but the effects of coffee drinking have yet to be investigated. Objectives: To retrospectively determine the temporal sequence of incident cigarette, coffee, and alcohol use and attributed subjective effects in AA participants. Methods: Volunteers at all Nashville open-AA meetings (n = 289 [126 women], completion rate = 94.1%) were administered a Lifetime Drinking History modified to also include lifetime cigarette and coffee consumption, as well as coffee consumption and effects questions, the Fagerstrom Test for Nicotine Dependence, and the Smoking Effects Questionnaire. Results: Average ages (years) at first regular use of alcohol, cigarettes, and coffee were 15.4 (IQR: 13.0-18.0), 16.7 (IQR: 13.0-18.5), and 18.5 (IQR: 14.0-23.5), respectively. In a subset who used all three substances (n = 236; 102 women) alcohol consumption preceded cigarette smoking (p < .001) and coffee drinking (p < .001), and cigarette smoking preceded coffee drinking (p < .001); these relationships did not differ by gender. Conclusions: Recovering alcoholics started regular alcohol consumption prior to cigarette smoking and coffee drinking. Scientific Significance: In AA participants, coffee does not precede initiation of regular smoking or alcohol drinking as might be anticipated for a gateway drug.

Reid LW; Elifson KW; Sterk CE. Ecstasy and gateway drugs: Initiating the use of ecstasy and other drugs. Annals of Epidemiology 17(1): 74-80, 2007. (46 refs.)

PURPOSE: The main purposes of this study are to examine whether and to what extent ecstasy use serves as a gateway to the use of such hard drugs as cocaine, heroin, and methamphetamine and compare ages of onset of alcohol and marijuana use and subsequent use of cocaine, heroin, and methamphetamine among young adult ecstasy users. METHODS: Face-to-face surveys were conducted with 268 young adult ecstasy users in Atlanta, GA. Subjects were solicited by using the community identification process, including targeted sampling and guided recruitment. Data analysis involved discrete-time event-history analysis. RESULTS: Results suggest that age of onset of ecstasy use influences the initiation of cocaine and methamphetamine use for our sample of active ecstasy users. In addition, alcohol and marijuana use precedes the initiation of cocaine and methamphetamine use, but only marijuana use influences the initiation of heroin use. CONCLUSIONS: The sequential progression of drug use proposed in the gateway literature is not immutable. Researchers must take into account the changing popularity of drugs over time, such as the emergence of ecstasy use, when identifying patterns of drug-use onset.

Riggs NR; Chou CP; Pentz MA. Preventing growth in amphetamine use: Long-term effects of the Midwestern Prevention Project (MPP) from early adolescence to early adulthood. Addiction 104(10): 1691-1699, 2009. (38 refs.)

Aim: The aim of the current study was to examine the long-term effect of an early adolescent substance abuse prevention program on trajectories and initiation of amphetamine use into early adulthood. Design: Eight middle schools were assigned randomly to a program or control condition. The randomized controlled trial followed participants through 15 waves of data, from ages 11-28 years. This longitudinal study design includes four separate periods of development from early adolescence to early adulthood. Setting: The intervention took place in middle schools. Participants: A total of 1002 adolescents from one large mid-western US city were the participants in the study. Intervention: The intervention was a multi-component community-based program delivered in early adolescence with a primary emphasis on tobacco, alcohol and marijuana use. Measures: At each wave of data collection participants completed a self-report survey that included questions about life-time amphetamine use. Findings: Compared to a control group, participants in the Midwestern Prevention Project (MPP) intervention condition had reduced growth (slope) in amphetamine use in emerging adulthood, a lower amphetamine use intercept at the commencement of the early adulthood and delayed amphetamine use initiation. Conclusions: The pattern of results suggests that the program worked first to prevent amphetamine use, and then to maintain the preventive effect into adulthood. Study findings suggest that early adolescent substance use prevention programs that focus initially on the 'gateway' drugs have utility for long-term prevention of amphetamine use.

Saddichha S; Sinha BNP; Khess CRJ. The role of gateway drugs and psychosocial factors in substance dependence in Eastern India. International Journal of Psychiatry in Medicine 37(3): 257-266, 2007. (39 refs.)

Objective: Western studies have identified the gateway patterns of substance use which lead the way from the so called "Soft Drugs" (like nicotine, etc.) to the "Hard Drugs" (like Opioids) [the Gateway hypothesis]. Nicotine and alcohol have been implicated as the most common initiating drugs in studies from different places, however, studies are lacking from this region. This study was designed to find the drugs of initiation and to understand the factors for initiation, maintenance, and relapse of these substances in persons dependent on them in Eastern India. Method: Seventy subjects with ICD 10 DCR diagnosis of substance dependence admitted consecutively in Center for Addiction Psychiatry, Central Institute of Psychiatry (CIP), Ranchi, were taken up for the study after taking written informed consent. A semi-structured questionnaire including the substance use part of Mini International Neuropsychiatric Inventory (MINI) was administered. Results: Alcohol and opioids were the most common drugs of dependence but nicotine and alcohol were found to be the most common initiating drugs in both alcohol and opioid groups. Persons dependent on opioids presented earlier for treatment, with earlier development of withdrawal symptoms and having completed lesser years of formal education, and had higher monthly incomes as compared to those dependent on alcohol. The most common psychosocial factors determining initiation and maintenance were peer pressure or curiosity. Conclusions: If adolescents and youth can be motivated to stay away even from the "gateway drugs" by targeting common initiation factors, it may lead to delay in dependence or possibly avoidance of development of dependence.

Tarter RE; Vanyukov M; Kirisci L; Reynolds M; Clark DB. Predictors of marijuana use in adolescents before and after licit drug use: Examination of the gateway hypothesis. American Journal of Psychiatry 163(12): 2134-2140, 2006. (33 refs.)

Objective: The authors investigated whether the transition from licit drug use to marijuana use is determined by particular risk factors, as specified by the gateway hypothesis. They also evaluated the accuracy of the "gateway sequence" (illicit drug use following licit drugs) for predicting a diagnosis of substance use disorder. Method: Boys who consumed licit drugs only (N = 99), boys who consumed licit drugs and then transitioned to marijuana use (gateway sequence) (N = 97), and boys who used marijuana before using licit substances (alternative sequence) (N = 28) were prospectively studied from ages 10 12 years through 22 years to determine whether specific factors were associated with each drug use pattern. The groups were compared on 35 variables measuring psychological, family, peer, school, and neighborhood characteristics. In addition, the utility of the gateway and alternative sequences in predicting substance use disorder was compared to assess their clinical informativeness. Results: Twenty-eight (22.4%) of the participants who used marijuana did not exhibit the gateway sequence, thereby demonstrating that this pattern is not invariant in drug-using youths. Among youths who did exhibit the gateway pattern, only delinquency was more strongly related to marijuana use than licit drug use. Specific risk factors associated with transition from licit to illicit drugs were not revealed. The alternative sequence had the same accuracy for predicting substance use disorder as the gateway sequence. Conclusions: Proneness to deviancy and drug availability in the neighborhood promote marijuana use. These findings support the common liability model of substance use behavior and substance use disorder.

Timberlake DS; Haberstick BC; Hopfer CJ; Bricker J; Sakai JT; Lessem JM et al. Progression from marijuana use to daily smoking and nicotine dependence in a national sample of US adolescents. Drug and Alcohol Dependence 88(2/3): 272-281, 2007. (41 refs.)

Background: While it has been demonstrated that smoking cigarettes in adolescence increases the likelihood of progressing to marijuana use, few studies have considered the reverse scenario in which early use of cannabis leads to greater tobacco smoking. Methods: Participants (n = 5963), who had never smoked cigarettes daily by wave I of the National Longitudinal Study of Adolescent Health, were followed 6 years (waves I-III) from adolescence into young adulthood. Measures of marijuana use (lifetime use, monthly use, age at first use), as assessed at wave I within 12-16 (n = 3712) and 17-21 (n = 2251) year-olds, were separately modeled as predictors of three tobacco-related outcomes: (1) age at onset of daily cigarette smoking, (2) lifetime nicotine dependence, (3) current nicotine dependence. Results: In the older cohort (17-21-year-olds at wave I), lifetime (> 10 times) and past-month marijuana use at wave I were predictive of an earlier initiation into daily cigarette smoking and a greater likelihood of developing nicotine dependence by wave III. Furthermore, age at first use of cannabis was negatively associated with risk of nicotine dependence in the older, but not younger cohort. Conclusion: After controlling for baseline measures of tobacco smoking and other demographic risk factors, the use of marijuana in adolescence was modestly associated with daily cigarette smoking and nicotine dependence in young adulthood.

Tomar SL. Is use of smokeless tobacco a risk factor for cigarette smoking? The U.S. experience. Nicotine & Tobacco Research 5(4): 561-569, 2003. (56 refs.)

Some researchers are promoting the use of smokeless tobacco as safer than cigarette smoking and as a possible method for quitting smoking, but smokeless tobacco might be a gateway drug that leads to smoking, and the availability and marketing of smokeless tobacco may keep smokers from quitting. This study assessed 4-year initiation rates of smokeless tobacco use and cigarette smoking in relation to each other and examined switching between the products. Data were from the 1989 Teenage Attitudes and Practices Survey and its 1993 follow-up study, comprising a nationally representative U.S. cohort of 7,960 people aged 11-19 years at baseline. Analyses were limited to males with complete data on smoking and smokeless tobacco use at both interviews (n=3,996). Young males who were not smokers in 1989 but regularly used smokeless tobacco were more than three times as likely as never users to be current smokers 4 years later (23.9% vs. 7.6%), adjusted OR = 3.45 (95% CI = 1.84-6.47). In contrast, 2.4% of current smokers and 1.5% of never smokers at baseline became current regular smokeless tobacco users by follow-up. More than 80% of baseline current smokers were still smokers 4 years later, and more than 40% of baseline current regular smokeless tobacco users became smokers either in addition to or in place of smokeless tobacco use. It appears that smokeless tobacco may be a starter product for subsequent smoking among young U.S. males but may have little effect on quitting smoking.

Tomar SL; Fox BJ; Severson HH. Is smokeless tobacco use an appropriate public health strategy for reducing societal harm from cigarette smoking? (review). International Journal of Environmental Research and Public Health 6(1): 10-24, 2009. (84 refs.)

Four arguments have been used to support smokeless tobacco (ST) for harm reduction: (1) Switching from cigarettes to ST would reduce health risks; (2) ST is effective for smoking cessation; (3) ST is an effective nicotine maintenance product; and (4) ST is not a "gateway" for cigarette smoking. There is little evidence to support the first three arguments and most evidence suggests that ST is a gateway for cigarette smoking. There are ethical challenges to promoting ST use. Based on the precautionary principle, the burden of proof is on proponents to provide evidence to support their position; such evidence is lacking.

Tomar SL; Loree M. Errors in analyzing associations between use of smokeless tobacco and cigarettes. (letter). Addiction 99(2): 260 -261, 2004. (2 refs.)

This letter is directed to an article published by LT Kozlowski et al, positing that smokeless tobacco use is not a causal gateway to cigarettes, Addiction 98(8).

Tullis LM; DuPont R; Frost-Pineda K; Gold MS. Marijuana and tobacco: A major connection? Journal of Addictive Diseases 22(3): 51-62, 2003. (21 refs.)

Smoking among teens and college students is a significant public health challenge. Tobacco, marijuana, and alcohol continue to be the most commonly abused drugs by teens and young adults. Educational efforts have resulted in increased awareness of the mortality and morbidity attributed to smoking, second-hand smoke, and prenatal exposure to tobacco. Short- and long-term consequences of marijuana use are well documented in the literature, but they have received less wide spread attention. Even less well known is the relationship between these substances. Does use of one lead to use of the other? Are there synergistic and/or antagonistic effects when these substances are used together? We need answers to these questions to understand the prevalence of use and the impact of these drugs on our nations youth and young adults. The gateway theory of drug use is often used to describe the progression from using alcohol or tobacco, to marijuana, and later use of other drugs like MDMA, cocaine, and heroin. While tobacco use does commonly precede marijuana use, we propose that marijuana may be a "gateway drug" to tobacco smoking. Our research with university students is suggesting that cigarette-smoking initiation often follows or coincides with marijuana use.

Van Gundy K; Rebellon CJ. A life-course perspective on the "gateway hypothesis". Journal of Health and Social Behavior 51(3): 244-259, 2010. (47 refs.)

Drawing on stress and life-course perspectives and using panel data from 1,286 south Florida young adults, we assess three critical questions regarding the role of marijuana in the "gateway hypothesis." First, does teen marijuana use independently (causally) affect subsequent use of more dangerous substances? Second, if so, does that effect apply to the abuse of other illicit substances, as defined by the DSM-IV, or only to the use of such substances? Finally, does any causal effect of teen marijuana use survive beyond adolescence, or is it a short-term effect that subsides as adolescents transition to adulthood? Our results indicate a moderate relation between early teen marijuana use and young adult abuse of other illicit substances; however, this association fades from statistical significance with adjustments for stress and life-course variables. Likewise, our findings show that any causal influence of teen marijuana use on other illicit substance use is contingent upon employment status and is short-term, subsiding entirely by the age of 21. In light of these findings, we urge U. S. drug control policymakers to consider stress and life-course approaches in their pursuit of solutions to the "drug problem."

van Leeuwen AP; Verhulst FC; Reijneveld SA; Vollebergh WAM; Ormel J; Huizink AC. Can the gateway hypothesis, the common liability model and/or, the route of administration model predict initiation of cannabis use during adolescence? A survival analysis-The TRAILS Study. Journal of Adolescent Health 48(1): 73-78, 2011. (31 refs.)

Purpose: There is substantial research linking tobacco and alcohol use to subsequent cannabis use, yet the specificity of this relationship is still under debate. The aim of this study was to examine which substance use model-the gateway hypothesis, the common liability (CL) model and/or the route of administration model-best explains the relationship between early onset of tobacco and alcohol use and subsequent cannabis use initiation. Methods: We used data from 2,113 (51% female) Dutch adolescents who participated in three consecutive assessment waves (mean age: 11.09, 13.56, and 16.27 years, respectively) of the TRacking Adolescents' Individual Lives Survey study. (Pre) adolescent cannabis, tobacco and alcohol use was assessed using the Youth Self-Report and a TRacking Adolescents' Individual Lives Survey developed questionnaire. Results: We found that, during adolescence, early onset of tobacco use does not pose a significantly higher risk of initiating cannabis use than early onset alcohol use. Therefore, we can rule out the route of administration model. Moreover, we found that adolescents who reported early onset comorbid use of both tobacco and alcohol have a higher likelihood to initiate cannabis use than adolescents who have tried either tobacco or alcohol. The gateway hypothesis is not broad enough to explain this finding. Therefore, the CL model best predicts our findings. Conclusion: Future research on adolescent cannabis initiation should focus on testing the robustness of the CL model. Furthermore, identifying adolescents who use both tobacco and alcohol, before the age of 13, may help to curtail the onset of cannabis use.

van Ours JC. Cannabis use when it's legal. Addictive Behaviors 32(7): 1441-1450, 2007. (15 refs.)

This paper addresses the question of whether alcohol and tobacco are "gateways" for cannabis use. To investigate this the relationships between the starting rates in the use of alcohol, tobacco, and cannabis are analyzed. The starting rate for cannabis use appears to be higher for smokers and lower for users of alcohol. Indeed, tobacco use seems to be a gateway for cannabis use. The main policy conclusion is that measures that reduce smoking will also reduce the incidence of cannabis use.

Weiner MD; Pentz MA; Skara SN; Li CY; Chou CP; Dwyer JH. Relationship of substance use and associated predictors of violence in early, middle, and late adolescence. Journal of Child & Adolescent Substance Abuse 13(2): 61-81, 2003. (33 refs.)

This study examined relationships among selected predictors of violence, including victimization, low conflict management efficacy, hostile anger and drug use in 8th-, 10th-, and 12th-grade adolescents. The study was a secondary analysis of data from a population-based, cross-sectional survey of health behaviors among adolescents (N = 3922). For each cohort, it was hypothesized that victimization and low conflict management efficacy would predict low hostile anger control, which would predict gateway drug use, and the subsequent development of hard drug use and violence. Overall model fit and the magnitude of specific paths were expected to increase across grades. Using structural equation modeling (SEM), results indicated acceptable model fit for 8th-grade (CFI = .95), 10th-grade (CFI = .93) and 12th-grade (CFI = .94) cohorts. Results suggest that the influence of relational victimization and conflict management efficacy on hard drug use may be mediated through low hostile anger control and gateway drug use.

Weiner MD; Pentz MA; Skara SN; Li CY; Chou CP; Dwyer JH. Relationship of substance use and associated predictors of violence in early, middle, and late adolescence (correction: vol 13, pg 61, 2004). Journal of Child & Adolescent Substance Abuse 13(4): 97-117, 2004. (34 refs.)

Wells JE; McGee MA. Violations of the usual sequence of drug initiation: Prevalence and associations with the development of dependence in the New Zealand Mental Health Survey. Journal of Studies on Alcohol and Drugs 69(6): 789-795, 2008. (32 refs.)

Objective: For 3 decades, studies have reported that the usual sequence of drug initiation is licit drugs, then cannabis, and then other illicit drugs. This article describes the prevalence of violations of this sequence, the predictors of violations, and the relationship between violations and the onset of alcohol or drug dependence. Method: The New Zealand Mental Health Survey is a nationally representative sample with 12,992 face-to-face interviews carried out in 2003-2004, The response rate was 73.3%. The World Health Organization Composite International Diagnostic Interview (CIDI 3.0) was used in the survey. Reports of the age at first use were obtained for alcohol and drugs but not for smoking. Results: Violations of the usual sequence of drug initiation were uncommon in the population (2.6%). Use of other illicit drugs before cannabis was the main violation, found in 2.3% of alcohol users, 3.0% of cannabis users, 8.6% of cocaine users, and 16.7% of those who had used other illicit drugs. Use of other illicit drugs before cannabis was more predominant in younger cohorts and those with more early-onset internalizing disorders. Violations had little association with the development of dependence in users when other important predictors such as age at onset of use and the number of illicit drugs used were taken into account. Internalizing disorders and early-onset bipolar disorder also predicted dependence. Conclusions: In New Zealand, violations of the gateway sequence are not common and they are not markers of progression to dependence.

Whalen CK; Jamner LD; Henker B; Gehricke JG; King PS. Is there a link between adolescent cigarette smoking and pharmacotherapy for ADHD? Psychology of Addictive Behaviors 17(4): 332-335, 2003. (17 refs.)

There is continuing concern that pharmacotherapy for attention-deficit/hyperactivity disorder (ADHD) may raise the risk of smoking (the gateway hypothesis). Alternatively, unmedicated people with ADHD may use nicotine to improve attentional and self-regulatory competence (the self-medication hypothesis). From a community sample of 511 adolescents participating in a longitudinal health study, 27 were identified as having ADHD, and 11 of these were receiving pharmacotherapy. Self-report surveys, electronic diaries, and salivary cotinine all indicated that adolescents treated with pharmacotherapy for ADHD smoked less than their untreated counterparts over 2 years of high school. These convergent findings from 3 disparate indicators tend support to the self-medication hypothesis over the gateway hypothesis, although alternative explanations need further study. The findings also suggest that early treatment of psychological and behavioral problems may prevent or delay smoking initiation.

Wodarz N; Kraus B; Kliegel P; Binder H; Johann M. Smoking in 9th graders is associated with higher alcohol and cannabis intake results from a representative questionnaire survey. Psychiatrische Praxis 34(Supplement 1): S73-S74, 2007. (8 refs.)

Objective: Cigarette smoking has been regarded as a gateway drug" for the use of other substances. This study aimed at elucidating the differences in consumption patterns between adolescent smokers and non-smokers. Methods: We surveyed a representative sample of 1580 9(th) graders by using a 26-item questionnaire. Results Students had a mean age of 15.3 years and had started smoking at a mean age of 12.3 years. 30 day-prevalence rate of smoking was 49.3% and lifetime prevalence was 77.3%. 30.8% of all students were daily smokers (girls 28.7%; boys 32.7%), 43% of them fulfilling the DSM-IV-criteria of tobacco dependence. 48% of the smokers had at least one smoking parent compared to 31% of non-smokers. In smokers, alcohol consumption and binge drinking were increased fourfold and threefold, respectively. Cannabis has been consumed by 40% of smokers compared to 6% of non-smokers. This percentage was even higher in students with a nicotine dependence. Conclusions: Primary prevention of tobacco smoking in adolescence might be an effective strategy in reducing the later consumption of alcohol and cannabis.

Wu ZH; Temple JR; Shokar NK; Nguyen-Oghalai TU; Graduatey JJ. Differential racial/ethnic patterns in substance use initiation among young, low-income women. American Journal of Drug and Alcohol Abuse 36(2): 123-129, 2010. (27 refs.)

Background: Accumulating research suggests that the gateway hypothesis of substance use may not apply equally across different race/ethnicity groups. Objectives: The current study examines racial and ethnic differences in patterns of initiation of licit and illicit substance use. Methods: A cross-sectional survey was conducted among 696 low-income women between the ages of 18 and 31 who sought gynecological care between December, 2001 and May, 2003 in southeast Texas. Results: Overall, White women fit the classic profile of drug use initiation patterns, with those initiating tobacco and beer/wine at earlier ages being more likely to use illicit drugs. Conversely, African-American and Hispanic women initiated tobacco and beer/wine at much later ages than White women, but they were as likely to use illicit drugs. Conclusions: To be optimally effective, prevention efforts may need to be tailored to fit the race/ethnicity of the audience. Further studies are suggested to investigate specific risk factors related to substance use initiation by race/ethnicity.