Beyond treatment effects: predicting emerging adult alcohol and marijuana use among substance-abusing delinquents.

Secondary analyses of a randomized clinical trial examined the effects of 4 putative risk factors and 2 protective factors in predicting drug use among 80 emerging adults treated 5 years earlier for delinquency and alcohol and/or marijuana use disorders. Frequency of marijuana use and the number of comorbid psychiatric disorders in adolescence predicted cannabis use in emerging adulthood. Increasing academic competence at high levels of social competence predicted less marijuana use. At emerging adulthood, greater use of alcohol and marijuana were associated with both criminality and psychopathology.