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Gateway Drug Theory


The "gateway drug theory" describes the phenomenon in which an introduction to drug-using behavior through the use of tobacco, alcohol, or marijuana is related to subsequent use of other illicit drugs. The theory suggests that, all other things being equal, an adolescent who uses any one drug is more likely to use another drug. In practice, early introduction to substance use for adolescents is often through tobacco and/or alcohol. These two drugs are considered the first "gate" for most adolescents. Under this hypothesis, tobacco, alcohol, and marijuana are all considered "gateway drugs," preceding the use of one another and of illicit drugs.

The National Center on Addiction and Substance Abuse (CASA) provides the following illustrations:

  • Among 12-to 17-year-olds with no other problem behaviors, those who drank alcohol and smoked cigarettes at least once in the past month are 30 times likelier to smoke marijuana than those who didn't. These correlations are more pronounced for girls than boys: for girls, 36 times likelier; for boys, 27 times likelier.
  • Among 12-to 17-year-olds with no other problem behaviors, those who used all three gateway drugs (cigarettes, alcohol, marijuana) in the past month are almost 17 times likelier to use another drug like cocaine, heroin, or LSD. These correlations are stronger for boys than girls: for boys, 29 times likelier; for girls, 11 times likelier.

These gates are prime targets for early intervention and prevention strategies. There is also a clear dose-response relationship between the quality and frequency of use of gateway drugs and the likelihood of subsequent illicit drug use.

Robert S. Gold

Blakely Pomietto

(see also: Alcohol Use and Abuse; Adolescent Smoking; Drug Abuse Resistance Education [DARE]; Marijuana; Smoking Behavior; Tobacco Control )


Drugs and Crime Prevention Committee (1997). Turning the Tide. Melbourne, Australia: Parliament of Victoria.

Kandel, D.; Yamaguchi, K.; and Chen, K. (1992). "Stages of Progression in Drug Involvement from Adolescence to Adulthood: Further Evidence for the Gateway Theory." Journal of Studies on Alcohol 53:447457.

The National Center for Addiction and Substance Abuse (1997). CASA Adolescent Commission Report: America's Children and Smoking, Drinking, and Using Drugs at the Youngest Ages Ever. Available at

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