Method. A randomized controlled intervention study is proposed. A total of 210 participants will be randomly assigned to two, respectively three study conditions: 1. ST (n=70) including motivational enhancement, cognitive-behavioral, and psychosocial problem solving treatment components, 2. TST (n=70), including the same components as the ST but partly individually matched to the specific problem profile of the patient, and (c) a delayed treatment control group (DTC, n=70). Core outcome variables are total quit rates, number of cannabis use in the past 4 weeks, decrease in ASI scores and retention rate. The core hypothesis will be tested in the combined ST/TST group (n=140). The ASI serves for the allocation algorithms in the TST group and serves as outcome measure for the 3rd hypothesis.