Initiation of Marijuana Use: Trends, Patterns, and Implications. Analytic Series.

Estimates of first-time drug use, referred to as incidence or initiation, provide an important measure of the Nation's drug use problem. They suggest emerging patterns of use and identify periods of heightened risk for an immediate focus on the prevention of substance use, particularly among children and youths. This report contains an analysis of the initiation of marijuana use. The analysis is based on data from the 1999 and 2000 National Household Surveys on Drug Abuse (NHSDAs). Overall estimates of the prevalence and rate of marijuana initiation based on combined 1999 and 2000 data were released in September 2001. Those results showed that, although there was a decrease in incidence from 2.6 million new users in 1996 to 2.0 million in 1999, these levels were still significantly higher than the levels in 1990 (1.4 million). The purpose of this report is to present more in-depth analyses of incidence rates among population subgroups, demographic characteristics and predictors of recent initiates, and consequences of early marijuana initiation. Specifically, this report has four objectives: estimate incidence rates and trends of marijuana use, provide State-specific incidence estimates, identify characteristics and predictors of recent marijuana initiates, and examine the relationship between early marijuana use and later drug use patterns. Three appendixes present the statistical methods and limitations of the data, provide selected standard error tables, and include selected questionnaire pages from the 1999 and 2000 NHSDAs. (Contains 58 references and 52 tables.) (GCP)