This Article  • Full text  • PDF  • Send to a friend  • Save in My Folder  • Save to citation manager  • Permissions  Citing Articles  • Citation map  • Citing articles on HighWire  • Citing articles on ISI (104)  • Contact me when this article is cited  Related Content  • Related article  • Similar articles in JAMA  Topic Collections  • Substance Abuse/ Alcoholism  • Alert me on articles by topic

Michael T. Lynskey, PhD; Andrew C. Heath, DPhil; Kathleen K. Bucholz, PhD; Wendy S. Slutske, PhD; Pamela A. F. Madden, PhD; Elliot C. Nelson, MD; Dixie J. Statham, MA; Nicholas G. Martin, PhD

JAMA. 2003;289:427-433.

Context  Previous studies have reported that early initiation of cannabis (marijuana) use is a significant risk factor for other drug use and drug-related problems.

Objective  To examine whether the association between early cannabis use and subsequent progression to use of other drugs and drug abuse/dependence persists after controlling for genetic and shared environmental influences.

Design  Cross-sectional survey conducted in 1996-2000 among an Australian national volunteer sample of 311 young adult (median age, 30 years) monozygotic and dizygotic same-sex twin pairs discordant for early cannabis use (before age 17 years).

Main Outcome Measures  Self-reported subsequent nonmedical use of prescription sedatives, hallucinogens, cocaine/other stimulants, and opioids; abuse or dependence on these drugs (including cannabis abuse/dependence); and alcohol dependence.

Results  Individuals who used cannabis by age 17 years had odds of other drug use, alcohol dependence, and drug abuse/dependence that were 2.1 to 5.2 times higher than those of their co-twin, who did not use cannabis before age 17 years. Controlling for known risk factors (early-onset alcohol or tobacco use, parental conflict/separation, childhood sexual abuse, conduct disorder, major depression, and social anxiety) had only negligible effects on these results. These associations did not differ significantly between monozygotic and dizygotic twins.

Conclusions  Associations between early cannabis use and later drug use and abuse/dependence cannot solely be explained by common predisposing genetic or shared environmental factors. The association may arise from the effects of the peer and social context within which cannabis is used and obtained. In particular, early access to and use of cannabis may reduce perceived barriers against the use of other illegal drugs and provide access to these drugs.

Author Affiliations: Queensland Institute of Medical Research, Brisbane, Queensland, Australia (Drs Lynskey and Martin and Ms Statham); Missouri Alcoholism Research Center and Department of Psychiatry, Washington University School of Medicine, St Louis (Drs Lynskey, Heath, Bucholz, Madden, and Nelson); and Missouri Alcoholism Research Center and Department of Psychology, University of Missouri, Columbia (Dr Slutske).

RELATED ARTICLE

Does Marijuana Use Cause the Use of Other Drugs?
Denise B. Kandel
JAMA. 2003;289(4):482-483.
EXTRACT | FULL TEXT  

THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES

Exposure to Terrorism and Israeli Youths' Cigarette, Alcohol, and Cannabis Use
Schiff et al.
Am. J. Public Health 2007;97:1852-1858.
ABSTRACT | FULL TEXT  

One relative risk versus two odds ratios: implications for meta-analyses involving paired and unpaired binary data
Zou
Clin Trials 2007;4:25-31.
ABSTRACT  

Cannabis use by children and young people.
McArdle
Arch. Dis. Child. 2006;91:692-695.
ABSTRACT | FULL TEXT  

Marijuana use is associated with a reorganized visual-attention network and cerebellar hypoactivation
Chang et al.
Brain 2006;129:1096-1112.
ABSTRACT | FULL TEXT  

Drug use desistance
Frisher and Beckett
Criminal Justice 2006;6:127-145.
ABSTRACT  

Reducing the Risk of HIV Infection Associated With Illicit Drug Use
Committee on Pediatric AIDS
Pediatrics 2006;117:566-571.
ABSTRACT | FULL TEXT  

Twin study shows cannabis makes moving to hard drugs more likely
Sheldon
BMJ 2006;332:197-197.
FULL TEXT  

Recreational drug consumers: who seeks treatment?
Siliquini et al.
Eur J Public Health 2005;15:580-586.
ABSTRACT | FULL TEXT  

Developments in the Epidemiology of Drug Use and Drug Use Disorders
Compton et al.
Am. J. Psychiatry 2005;162:1494-1502.
ABSTRACT | FULL TEXT  

Influences of Parenting Practices on the Risk of Having a Chance to Try Cannabis
Chen et al.
Pediatrics 2005;115:1631-1639.
ABSTRACT | FULL TEXT  

Major Depressive Disorder, Suicidal Ideation, and Suicide Attempt in Twins Discordant for Cannabis Dependence and Early-Onset Cannabis Use
Lynskey et al.
Arch Gen Psychiatry 2004;61:1026-1032.
ABSTRACT | FULL TEXT  

Prevalence of Marijuana Use Disorders in the United States: 1991-1992 and 2001-2002
Compton et al.
JAMA 2004;291:2114-2121.
ABSTRACT | FULL TEXT  

RE: "ESTIMATING THE RELATIVE RISK IN COHORT STUDIES AND CLINICAL TRIALS OF COMMON OUTCOMES"
Cummings
Am J Epidemiol 2004;159:213-213.
FULL TEXT  

Early Reactions to Cannabis Predict Later Dependence
Fergusson et al.
Arch Gen Psychiatry 2003;60:1033-1039.
ABSTRACT | FULL TEXT  

Early Exposure to Marijuana and Risk of Later Drug Use
Schier et al.
JAMA 2003;290:329-329.
FULL TEXT  

Early Exposure to Marijuana and Risk of Later Drug Use
Anand
JAMA 2003;290:330-330.
FULL TEXT  

Early Exposure to Marijuana and Risk of Later Drug Use--Reply
Kandel
JAMA 2003;290:331-332.
FULL TEXT  

Early Exposure to Marijuana and Risk of Later Drug Use
Cummings
JAMA 2003;290:329-329.
FULL TEXT  

Early Exposure to Marijuana and Risk of Later Drug Use
Macleod et al.
JAMA 2003;290:329-330.
FULL TEXT  

Is Marijuana a Gateway Drug?
Journal Watch Dermatology 2003;2003:17-17.
FULL TEXT  

Twin Study Adds Fuel To Marijuana Debate
Bender
Psychiatr. News 2003;38:34-52.
FULL TEXT  

Early Marijuana Use May Lead to Use of Other Drugs and Alcohol
JWatch Emergency Med. 2003;2003:9-9.
FULL TEXT  

Early Marijuana Use Predicts Further Substance Abuse
JWatch Psychiatry 2003;2003:3-3.
FULL TEXT  

Is Marijuana a Gateway Drug?
JWatch General 2003;2003:1-1.
FULL TEXT  

Cannabis Use: The Slippery Slope Theory Finds Solid Ground
JWatch Pediatrics 2003;2003:11-11.
FULL TEXT  

Does Marijuana Use Cause the Use of Other Drugs?
Kandel
JAMA 2003;289:482-483.
FULL TEXT