Substance Use Trajectories From Early Adolescence Through the Transition to College.
The transition to college is an important developmental period for the development of alcohol, marijuana, and hard drug (cocaine, opiates, inhalants, stimulants, hallucinogens, Ecstasy, club drugs) use. The current study explored specific changes in substance use patterns during and after the transition to college through the use of trajectory analyses. Participants were 526 students who reported retrospectively and prospectively on their substance use from age 13 through the junior year of college. Group-based trajectory modeling was used to estimate developmental trajectory groups for alcohol, marijuana, and hard drug use during this period. Results supported a five-group model of alcohol use, a four-group model of marijuana use, and a four-group model of hard drug use. Although three of the five alcohol trajectories indicated high escalation throughout adolescence, one of these groups decreased in alcohol use dramatically during the freshman and sophomore years, a trend also found for hard drug use. Trajectories demonstrated significant differences in terms of gender, race, and impulsive personality characteristics. These results indicate that the start of college is an important developmental transition in terms of polysubstance use, and that despite the homogeneity of this undergraduate sample, there is considerable divergence in trajectories during college.