Factors associated with regular marijuana use among high school students: a long-term follow-up study.

The present study investigated whether several behavioral and psychosocial factors measured during early adolescence predicted regular marijuana use 6 years later in a sample of high school students. As part of a school-based survey. 7th-grade students (N = 1,132) reported levels of alcohol, tobacco, and marijuana use, and were assessed on several domains of psychosocial functioning potentially relevant in the etiology of marijuana use. When students were followed-up in the 12th-grade, 14% smoked marijuana on a regular basis (once or more per month). Findings indicated that early cigarette smoking, alcohol use, and alcohol intoxication predicted later regular marijuana use. For boys, early marijuana use increased the odds for later regular marijuana use. Cigarette smoking by friends and siblings during early adolescence also increased the likelihood of later monthly marijuana use. The findings suggest that early prevention programs for adolescent alcohol, tobacco, and/or other drug use may have important preventive effects in terms of potentially more serious levels of marijuana involvement later in adolescence and early adulthood.