Patterns of cannabis use, abuse and dependence over time: incidence, progression and stability in a sample of 1228 adolescents

Aims. To present data on the incidence of cannabis use at follow-up, and it s progression, stability, abuse and dependence in a representative sample o f adolescents (N = 1228), aged 14-17 years at "baseline"-the outset of the study-in Munich, Germany. Design. The study employed a prospective longitud inal design using a representative population sample. The mean follow-up ti me was 19.7 months. The Composite International Diagnostic Interview (M-CID I) was used to assess patterns of use, abuse and dependence according to DS M-IV criteria. Findings. (I) In our sample, 34.8% of males and 30.2% of fem ales had tried cannabinoids at least once. (2) Of those who used cannabis r epeatedly (two or four times) at baseline, 26.1% stopped using by follow-up ; the majority went on to regular use in the follow-up period Similarly, on ly 17.7% of the regular users at the outset slopped using cannabis complete ly; 74.2% continued their pattern of regular use. Thus, the higher the base line use pattern, the higher was the probability of continued or heavier us e during follow-up. (3) Although the cumulative life-time incidence for DSM -IV cannabis abuse (3.5%) in this age group was low, it is noteworthy that complete diagnostic remissions were relatively rare (31.7% for dependence, 41.1% for abuse). (4) There was considerable concurrent use of other drugs. Conclusions. Cannabis use was almost as widespread in this sample of adole scents in Germany as in similar age groups ill metropolitan areas of North America. There was a relatively low spontaneous remission rate among regula r and repeated users. Cannabis use in adolescence appears to be less transi ent than many people would believe.