Research & Initiatives
Biobehavioural Addictions and Concurrent Disorders Research Laboratory (BACDRL) at CAMH focuses on understanding and treating substance use disorders (e.g. cannabis and tobacco) in people with serious mental illness, with a focus on drug abstinence, neurocognition and neuromodulation.
Effects of Extended Cannabis Abstinence on Clinical and Cognitive Outcomes in Patients with Co-Morbid Major Depressive and Cannabis Use Disorders (MADCAN-II)
Major depressive disorder (MDD) is a devastating psychiatric illness that causes impairment across domains of everyday life. Cannabis is a highly prevalent (~15% of the general population) and legalized recreational drug (as of October, 2018) that may exacerbate the symptoms of major depressive disorder. Significant co-occurance of MDD and cannabis use, particularly cannabis use disorder (CUD) currently exists in this population. Cannabis may negatively impact the course of MDD, decrease age of onset, worsen severity of depressive episodes and significantly reduces quality of life. This study aims to look at the impact reductions in cannabis use and cannabis abstinence on mood, anxiety, sleep, cognition, motivation, and functional outcomes.
Budtender Knowledge on Cannabis and Mental Illness
Canada legalized recreational (non-medical) cannabis use in 2018, and cannabis products are sold in legal cannabis stores operated by each province and territory. The salespeople who work in these legal cannabis stores are conventionally known as “Budtenders”, and are the frontline to cannabis customers, advising them on all aspects of cannabis products, including on behavioural and mental health effects, such as mood and anxiety, sleep, psychosis and cognition. However, it is not clear whether the information imparted to customers is consistent with the scientific evidence. We recently conducted a pilot study of southern Ontario Budtenders (N=46) with respect to perceptions and knowledge about cannabis and mental health (Lowe, DJE et al., 2025. Cannabis, in press), supported by the Alcohol and Gaming Commission of Ontario (AGCO), the regulators of Ontario Cannabis Stores. We found that: 1) there were significant inconsistencies between Budtender knowledge about the mental health effects of cannabis and the scientific evidence; 2) Budtenders tended to get their knowledge about cannabis from non-scientific sources, including the internet and personal experience. We now propose a larger study (N=300) of Budtender knowledge of cannabis and mental illness across the Province of Ontario. We hypothesize that there will be inconsistencies between knowledge and perceptions of cannabis in mental illness, and that this may relate to a lack of robust educational training for Budtenders. The proposed research is important since it will identify gaps in Budtender knowledge that can be remediated with more robust, evidence-based Budtender training and education. This could improve customer experience and safety outcomes with respect to cannabis use amongst people with or at risk for mental illness who seek to use non-medical cannabis.