Background: As cannabis regulation expands, it is important to understand who enrolls in legal non-medical cannabis programs and how participant profiles relate to harm. We identified participant profiles in Geneva’s pilot trial, La Cannabinothèque, using motives for cannabis use, knowledge of lower-risk use, and perceived risk, and examined differences in key outcomes.

Methods: Baseline data from 1290 people who use cannabis (PWUC) were analysed. Hierarchical clustering (Ward) followed by K-means refinement supported a four-cluster solution (Cramer’s V = 0.563). Clusters were compared on problematic cannabis use and consumption frequency, mental health symptoms, and quality of life.

Results: Cluster 1 (High motives – Low safer-use knowledge – Moderate risk perception; 9.9%) showed high endorsement of all motives, lower-risk knowledge, and moderate to elevated perceived risk, and had the highest problematic use/frequency and poorer health indicators. Cluster 2 (Moderate motives – Average safer-use knowledge – Low risk perception; 26.7%) had moderate motives (relatively higher enhancement/social), average knowledge, lower perceived risk, and the lowest problematic use with better health indicators. Cluster 3 (Low motives – High safer-use knowledge – High risk perception; 29.4%) combined low-to-average motives with the highest knowledge and perceived risk, yet showed frequent use and problematic use comparable to Cluster 1. Cluster 4 (Minimal motives – Low safer-use knowledge – Very low risk perception; 34.0%) reported minimal motives, low knowledge and perceived risk, and low use/cannabis-related harms; members were older with later initiation.

Conclusions: Findings support the link between coping-related motivation and problematic use, but the high-risk profile of Cluster 3 despite strong knowledge and risk awareness suggests that information and perception alone may not reduce harm. Profile-tailored harm reduction and integrated support may be needed within regulated cannabis frameworks.