Bongs, a method of using cannabis linked to dependence.

Participants were 390 students (221 boys, 169 girls; mean age 17.1 years, SD 1.1; range 15 to 20 years). They were drawn from a random sample of 14 classes from 3 secondary and grammar schools in the departments of Haute-Garonne and Pyrénées-Orientales, France. Participants completed a questionnaire assessing the frequency and preferred method of cannabis use. We assessed cannabis dependence according to DSM-IV criteria (1), using a self-report questionnaire derived from the Mini International Neuropsychiatric Interview (MINI) (2). This questionnaire comprised 7 items corresponding to DSM-IV criteria for substance dependence. Participants received a diagnosis of cannabis dependence if they met 3 or more of the 7 DSM-IV criteria. The questionnaire validity had been assessed in a preliminary study (n = 23 adolescents). In the preliminary study, the questionnaire was followed after 8 to 15 days by a clinical interview that employed the MINI module for assessing substance dependence. Agreement between the questionnaire and the interview for the diagnosis of cannabis dependence was evaluated with Cohen’s kappa coefficient, which was judged satisfactory at 0.79. Cronbach’s alpha coefficient of this questionnaire was 0.76.