Einstieg, Abstieg, Ausstieg – Empirische Zusammenhangsanalysen zur Vorhersage des Beginns und Verlaufs des Konsums von Cannabis

Cannabis is the most common illegal substance used in Germany, and the use of cannabis and its consequences is an avoidable risk. Research on factors influencing cannabis use can help to identify vulnerable groups and to predict the progression of cannabis use. It also helps to develop specific measures for prevention and health promotion. The present work is a compilation of three studies that examine the prediction of the onset and course of cannabis use. One study focuses on predictors of the onset of cannabis use, two studies are related to factors that predict the course of cannabis use: the development of risky use and cessation of cannabis use. A longitudinal study with 3,040 students (mean age at baseline: 14.8 years) was conducted to examine which factors predict the initiation of cannabis use, and whether the use of e-cigarettes increased the risk of initiating cannabis use. Prior e-cigarette use nearly doubled the risk to try cannabis (RR: 1.83). The association was independent of sociodemographic and personal characteristics of the students and independent of the cannabis use of the peers. An additional interaction analysis also provided evidence that the association between e-cigarette use and cannabis use was stronger among adolescents who showed a lower overall risk to use substances in general. The second and third study analyzed factors that predicted the progression of cannabis use via an online survey. To study the factors associated with risky cannabis use, a total of 7,671 cannabis users (mean age = 21.8 years), who had used cannabis within the last 12 months were surveyed within a retrospective cohort study. Risky cannabis use (SDS > 3) was predicted by male gender, higher age, migration status, higher sensation seeking, earlier onset of cannabis use, more frequent cannabis use among peers during school time, less stable relationship with parents, and less parental mental health. To examine factors that predicted cessation of cannabis use, a sub-sample of 6,467 cannabis users were analyzed, who had at least three years of consumption experience. Cessation was predicted by older current age, being female, non-migrant status, less sensation seeking, using psychological treatment, more peer cannabis use during youth and a more negative first experience with cannabis. An additional predictor was a lower increase in the frequency of cannabis use in the first three years of use. The three studies demonstrate that the trajectories and the influencing factors of cannabis use are diverse. Some of the factors that predict the onset and further course of cannabis use are potentially malleable and are therefore of particular interest for prevention and health promotion. The results also show that use patterns are determined early on and that prevention measures should therefore be established as early as possible in adolescence. For the future, it is important to further research which measures most effectively influence the use behavior of young people and at which age. Preventive measures should also focus on peer influences and the parental home and expand the prevention measures or adapt them to ensure that these important factors are taken into account.