Cannabis and Polysubstance Use
Schütz, C.
The aim of CAPU project was to understand the role of cannabis use on mental health and substance disorders. CAPU had three complementary objectives, with a project to match each of the following objectives.
Aim 1: To summarize existing knowledge on cannabis effects in polysubstance users during treatment. We conducted a systematic review on cannabis and stimulant use and its relationship with substance use disorder treatment. Currently, evidence on relationships between cannabis and stimulant use is inconsistent, methodology is highly variable. We found there is little, if any, evidence that cannabis use improves treatment outcomes, with some studies providing evidence of additional cannabis use being associated with more detrimental outcomes.
Aim 2: To assess cannabis use in a treatment setting for concurrent mental health and substance use disorders by administering a cross-sectional survey. Later age of onset of cannabis use was associated with anxiety, psychoticism, and anger-hostility symptoms in concurrent disorder inpatients. Frequency of cannabis use was not related to mental health symptoms.
Aim 3: Conduct a translational neuropharmacological study to examine the effects of cannabinoids on stress in healthy adults. This study is ongoing.
Conclusions: Currently, evidence on cannabis and its relationships with substance use and mental health disorders is mixed. Age of cannabis use onset may be relevant for mental health outcomes. Further research on associations between cannabis use, mental health, and substance use is needed, especially in the context of legalization of recreational cannabis.