Abstract
A progressive and hierarchical sequence of drug use suggests that a sequence of stages of drug use can describe the order by which adolescents try drugs. We propose an operational definition to test gateway relations by providing a framework with the aim of describing a set of conditions to guide the evaluation of whether a drug serves as a gateway for another drug. We used data from the National Longitudinal Study of Adolescent Health to demonstrate how using latent transition analysis we can estimate the odds of using a drug at a later time conditional on having used a gateway drug at an earlier time. We provide three empirical demonstrations for testing the gateway relations using a national and longitudinal data of adolescents (e.g., gateway relation between cigarettes and marijuana, alcohol and marijuana, and alcohol and cigarettes).