Predictors of gateway between adolescent marijuana use and adult drug use

Title: Predictors of Gateway between Adolescent Marijuana Use and Adult Drug Use Introduction: Gateway theory predicts that the use of marijuana in adolescence may increase the risk of use of harder drugs later in life. This project seeks to test the gateway hypothesis using a large nationally representative dataset, and test which adolescent characteristics may predict which individuals follow the gateway progression. Methods: Data from Waves I and III of the National Longitudinal Study of Adolescent Youth (Add Health) were used (n=14,322). Logistic regression was used to predict drug use in adulthood from marijuana use in adolescence, and then to test which adolescent characteristics (including parental alcohol use, social support, and mental health) predict which adolescents who try marijuana will try harder drugs in adulthood. Results: Ever use of marijuana in adolescence was positively correlated with drug use in adulthood after adjusting for age at Wave I, race, and gender. Those who had tried marijuana in adolescence were about 3 times more likely to have used marijuana, about 4 times more likely to have used cocaine, and about 5 times more likely to have used meth in the past year as an adult (at Wave III). Results of the second part of the project are pending and will be complete at time of the conference. Conclusions: Adolescents who use marijuana may be more likely to use marijuana and other drugs as an adult.