Nadine Heckel holds a PhD in Psychology from the University of Zurich, where her doctoral research examined approaches to promoting lower-risk cannabis use within the framework of regulated cannabis sales. As part of the Addictive Disorders Research Group, she contributes to the “Züri Can – Cannabis mit Verantwortung” (“Cannabis with Responsibility”) study, conducted in collaboration with the City of Zurich. She previously earned a Master’s degree in Social and Organisational Psychology from the University of Exeter and a Bachelor’s degree in Socioeconomics from Friedrich-Alexander-Universität Erlangen-Nürnberg. Her interdisciplinary academic background combines psychological, social, and economic perspectives on cannabis use and public health.

Abstract

Improving lower-risk cannabis use knowledge and behaviour: Longitudinal evidence from Züri Can

Aims: With our ongoing longitudinal study Züri Can, we want to examine whether strictly regulated access to legal THC-cannabis through 10 pharmacies, 10 Social Clubs, and the Drug Information Center can help improve participants’ knowledge and behaviour regarding various aspects of lower-risk cannabis use, such as using cannabis without tobacco. Points of sale types may differ in how well they promote lower-risk use practices among participants.

Methods: Participants complete online surveys at six-month intervals. To measure lower-risk cannabis use knowledge (LRCU-K) and behaviour (LRCU-B), we used two scales containing 12 items each to produce a total sum score (0–48). We used Generalised Estimating Equations with exchangeable working correlations to analyse the two scales, adding time, type of point of sale, and their interaction as predictors.

Results: By 31 December 2025, 3102 participants completed a baseline survey and up to four follow-ups. At baseline, mean sum scores were similar for LRCU-K (34.35, SD=6.21) and LRCU-B (35.70, SD=6.08). At Social Clubs, the LRCU-K score was lower compared to pharmacies (b= -0.48; p=0.002). Across all point of sale types, LRCU-K increased by 0.80 and LRCU-B by 0.85 points per year.

Conclusions: Across all point of sale types, participants’ knowledge and behaviour regarding lower-risk cannabis use improved slightly over time. While participants at Social Clubs had slightly lower knowledge scores than those at pharmacies, regulated access to cannabis may provide a suitable framework for increasing awareness and promoting lower-risk use practices. More substantial changes in long-established use habits likely require more time and targeted interventions.