Legal substance use and the development of a DSM-IV cannabis use disorder during adolescence: the TRAILS study.

AIMS: To examine whether early onset of tobacco or alcohol use, and continued use of tobacco or alcohol in early adolescence, are related to a higher likelihood of developing a cannabis use disorder during adolescence.

DESIGN AND SETTING: Data were used from four consecutive assessment waves of the TRacking Adolescents' Individual Lives Survey (TRAILS), a general Dutch population study. TRAILS is an ongoing longitudinal study that will follow the same group of adolescents from the ages of 10 to 24 years.

PARTICIPANTS: The sample consisted of 1108 (58% female) adolescents (mean ages at the four assessment waves are 11.09, 13.56, 16.27 and 19.05 years, respectively)

MEASUREMENTS: Cannabis use disorders were assessed using the Composite International Diagnostic Interview 3.0 (CIDI). Adolescent tobacco and alcohol use were assessed using self-report questionnaires.

FINDINGS: Early-onset tobacco use [odds ratio (OR) = 1.82, confidence interval (CI) = 1.05-3.14, P < 0.05], but not early-onset alcohol use (OR = 1.33, CI = 0.84-2.12, P > 0.05), was associated with a higher likelihood of developing a cannabis use disorder. Similarly, adolescents who reported continued use of tobacco (OR = 2.47, CI = 1.02-5.98, P < 0.05), but not continued use of alcohol (OR = 1.71, CI = 0.87-3.38, P > 0.05), were more likely to develop a cannabis use disorder.

CONCLUSIONS: Early-onset and continued tobacco use appear to predict the development of a cannabis use disorder in adolescence, whereas early onset and continued alcohol use do not.