Young adults experience many changes during the transition to college, including changes to their substance use risk factors and patterns. While there are often high rates of use during late adolescence and young adulthood, individuals’ substance use varies over time. This has lead researchers to believe that including these adolescent years in substance use trajectories could provide information about how substance use patterns change during the transitional period from early adolescence through emerging adulthood. This study examines the progression of alcohol, marijuana, and hard drug use from age 13 through the junior year of college. First-year college students (N = 526) were selected to participate in the study and were assessed for 3 years. Participants retrospectively reported their substance use from age 13 to the present, then past-year use was assessed during the second and third years. Impulsive personality traits, delinquency, and violence were also assessed in the third year of the study. The majority of students reported alcohol use (94.8%), 60.3% reported marijuana use, 24.7% reported misuse of prescription stimulants, and 20.5% reported opiate use. Alcohol use was divided into five groups, while marijuana and hard drug use were divided into four groups. Nil to low drinkers had modest use throughout college. Moderate drinkers had relatively stable use throughout college. Experimenters had a peak in alcohol use during the end of high school/beginning of college. Late-onset drinkers had peak increases just before college entry and had continued increases throughout college. Early-onset drinkers escalated their use though high school and maintained a high level of drinking through college. Occasional marijuana users initiated low marijuana use during high school which gradually decreased through college. Moderate marijuana users had steady use with a peak in high school, followed by a decline throughout college. High marijuana users initiated marijuana use much earlier (around age 13) with steep increases throughout high school and subtle decreases during college. Hard drug experimenters had steep increases in polydrug use up to college entry that declined to almost no use during the third year. Late-onset heavy users of hard drugs increased polydrug use from freshman to junior year. Early-onset hard drug users used more than one type of drug during high school, with subtle declines throughout college.
Take away: This study identifies five trajectories for alcohol use, four for marijuana use, and four for hard drug use that provide useful information about the progression of substance use over time. Some of these trajectories and patterns of alcohol and substance use are time limited and unique to a certain period. For example, experimenters have escalated use up until college entry. These findings can influence the development of campus prevention and intervention strategies targeting these specific groups. Addressing more than one of these trajectories could serve as a promising multi-tiered intervention.