Developmental trajectories of marijuana use from adolescence to adulthood: Personal predictors

Objective: To investigate the relationship between early adolescent personal characteristics and the developmental trajectories of marijuana use extending from early adolescence to adulthood. Design: This study used a longitudinal design. Data were obtained using structured questionnaires administered by trained interviewers. Setting: Interviews were conducted in the participants' homes in upstate New York. Participants: Participants were drawn from a randomly selected cohort and were studied prospectively since 1975 (T1) at a mean age of 6 years. The follow-up data used for this study were collected at 6 time points when the participants were aged between 14 and 37 years in 1983 (T2), 1985-1986 (T3), 1992 (T4), 1997 (T5), 2002 (T6), and 2005-2006 (T7). Main Outcome Measures: Developmental trajectories of marijuana use. Results: Semiparametric group-based modeling and logistic regression analyses were used to analyze the data. The following5distinct trajectories of marijuana use were identified: nonusers or experimenters, occasional users, quitters or decreasers, increasingusers, and chronicusers. Chronic userscomparedwith other groups studied (nonusers or experimenters, occasional users, quitters or decreasers,andincreasing users) reported low self-control, externalizing behavior, and an orientation to sensation seeking. Conclusions: Personal attributes of low self-control, externalizing behavior, and an orientation to sensation seeking have long-term predictivepowerfor distinct trajectories of marijuana use over time. The importance of these findings or prevention and treatment programs is discussed.