[A survey on trials focussing on the treatment of cannabis-dependence]

Epidemiological studies show that the prevalence of cannabis use in Germany is approaching that of countries known for their high consumption rate, such as Australia and some parts of the USA. In these countries, the resulting cannabis-related psychosocial damage has led to mainly psychotherapeutic treatment studies (conducted in the past ten years) that will be introduced here. According to these studies, the optimal treatment of cannabis-dependent adults would be a short intervention which consists of a combination of motivational-enhancement and cognitive-behavioural elements as well as individual case-counselling (c. f. "Marihuana Treatment Project"). In parallel to a clear consume-reduction over time, these interventions were associated with abstinence rates between 15 % and 22 % also in longer follow-ups (greater than 12 months). Additionally, an approximately 50 % reduction of cannabis-related problems was described. Without any specific treatment, however, abstinence rates were found to be only between 0 % and 9 %, also without any change in prominent social problems. A similar though less obvious trend occurred in a large multisite study regarding the specific treatment of young people, in which besides motivational and cognitive-behavioural also milieu and family therapeutic interventions were tested (c. f. "Cannabis Youth Treatment"). Unfortunately, there exists no controlled treatment study up to now that considered a relevant psychiatric co-morbidity, which usually accompany cannabis-dependence. Whether the interventions above can be recommended and implemented under German conditions should be further investigated, especially considering the growing number of cannabis-consumers seeking treatment.