Cigarettes, alcohol, marijuana, other risk behaviors, and American youth

Increases in adolescent marijuana and other drug use have created widesprea d concern. One theory argues that increased use of cigarettes and alcohol a mong younger adolescents leads to greater use of marijuana which, in turn, leads to subsequent use of other drugs (e.g. cocaine, heroin, hallucinogens ). Detractors of this theory claim that use of these substances is a sympto m of a larger set of destructive behaviors (e.g. violence, suicide, promisc uous sex), and marijuana has no independent effect on the use of other more serious drugs. The authors examined whether, for high school seniors, earl y use of cigarettes, alcohol and marijuana has an independent effect on mor e serious drug use even when other behaviors are considered. Using the 1995 Youth Risk Behavior Survey (n = 2871) and logistic analysis, after account ing for selected other behaviors, seniors using cigarettes before age 13 we re 3.3 (95% C.I. 2.3,4.6) times likelier to have used marijuana than ones w ho never smoked; for alcohol, the odds ratio was 4.5 (2.6,7.7). Seniors usi ng marijuana before the age of 14 were 7.4 times (4.0,13.6) likelier to hav e used other drugs. Though no causal effect is demonstrated, cigarette and alcohol use was associated with the likelihood of marijuana use; marijuana use was associated with the likelihood of other drug use, even after select ed other risk and protective behaviors were considered. (C) 1999 Elsevier S cience Ireland Ltd. All rights reserved.