Daily patterns of alcohol, cigarette, and marijuana use in adolescent smokers and nonsmokers.

Timeline followback (TLFB) methodology was used to assess the daily use of cigarettes, alcohol, and marijuana in adolescent cigarette smokers and nonsmokers over the prior 30 days. Adolescent smokers reported more frequent daily use of both alcohol and marijuana than nonsmokers did. Of those smokers and nonsmokers who drank alcohol and used marijuana, smokers reported more frequent daily use of alcohol, but not marijuana. In examining daily use patterns, there were very few instances when adolescent smokers used alcohol but did not smoke cigarettes, and smokers used marijuana alone on more days than alcohol alone. One-fifth of the adolescent smokers used all three substances on the same day in the past month. There were no significant differences in the patterns of alcohol and marijuana use between female and male smokers, regardless of age. Implications for clinical interventions and future research are discussed.