The Partners for Change Outcome Management System in the psychotherapeutic treatment of cannabis use: a pilot effectiveness randomized clinical trial

Purpose: The aim of the study was to investigate the effectiveness of the Partners for Change Outcome Management System (PCOMS) in improving the retention rate and reducing drug use in a clinic for drug use treatment.

Material and methods: One-hundred outpatients with cannabis use as the primary presenting problem were randomized to either the PCOMS (n = 51) or treatment as usual (TAU; n = 49). Eight weekly psychotherapy sessions were planned in both conditions. The primary outcome was treatment retention measured as the rate of attendance to planned treatment sessions and dropout. The secondary outcomes were current cannabis and other drug use assessed with the European Addiction Severity Index (EuropASI). Several explorative outcomes were analyzed. Blind assessments of drug use were conducted three and six months after baseline. Outcome analyses were conducted on both the treated sample with at least one psychotherapy session (n = 82) and the intention-to-treat sample (n = 100).

Results: The results showed no incremental effect of the PCOMS compared to the TAU condition, for neither treatment retention, drug use, or therapeutic alliance.

Conclusion: The main findings align with previous studies that have found no effect of the PCOMS when employing outcome measures independent from the PCOMS intervention. The results are interpreted with caution due to implementation difficulties, which at the same time suggest challenges when employing the PCOMS in large outpatient clinics for drug use treatment.