What are the high risk periods for incident substance use and transitions to abuse and dependence? : implications for early intervention and prevention

Background: For a better understanding of the evolution of addictive disorders and the timely initiation of early intervention and prevention, we have to learn when and how quickly the critical transitions from first substance use (SU) to regular use and from first SU and regular SU to abuse and dependence occur. Little data are currently available on the transitions to substance use disorders (SUDs) across the spectrum of legal and illegal drugs taking into account gender differences. It is the aim of this paper to describe the high density incidence and transition periods of SU and SUD for alcohol, nicotine, cannabis and other illicit drugs for young males and females. Methods: A sample of (N = 3021) community subjects aged 14-24 at baseline were followed-up prospectively over 10-years. SU and SUD were assessed using the DSM-IV/M-CIDI. Results: Ages 10-16 are the high risk period for first alcohol and nicotine use (up to 38% of subjects start before age 14). Onset of illegal SU occurs later. Substantial proportions of transitions to regular SU and SUD occur in the first three years after SU onset. Only few gender differences were found for time patterns of SU/SUD incidence and transition. Conclusion: Except for alcohol the time windows for targeted intervention to prevent progression to malignant patterns in adolescence are critically small, leaving little time for targeted intervention to prevent transition. The fast transitions to abuse and dependence in adolescence may be indicative for the increased vulnerability to substance effects in this time period. Basic research on the determinants of transitions should thus target this period in adolescence.