Background: Cannabis use is widespread in people with psychosis, occurring in about 50% of these adults. Cannabis use is associated with an adverse course for psychotic disorders (e.g., more severe psychiatric symptoms, poorer psychosocial functioning). Few interventions exist to address cannabis use in this population. Additionally, patient preferences in this population for cannabis interventions are understudied. It is timely to execute a systematic review to identify effective cannabis preventive interventions for people with psychosis and conduct a patient preference survey of such interventions. These studies would address important research gaps, and would represent important key milestones towards developing an intervention to reduce harms associated with cannabis use in this population.
Objectives: 1) Finalize a systematic review to determine best practices for cannabis preventive interventions for people with psychosis and 2) conduct a survey of people with psychosis who use cannabis to document preferences for cannabis interventions.
Methods: 1) Review: Six databases were searched. Two reviewers assessed eligible studies for effectiveness and reporting quality. Intervention effectiveness was measured by analyzing cannabis-related harm and use outcomes. Our results suggested that no intervention targeting cannabis use emerged as clearly efficacious. 2) Survey: A cross-sectional survey including discrete choice experiment (DCE) methodology was developed. This survey will be administered to youth with early psychosis who use cannabis to elicit their online intervention preferences based on intervention attributes relating to: modality, booster sessions, and trial design. Data analyses of the DCE section will be conducted using three Mixed Rank-ordered Logit models to identify the variables that most strongly predict the participants' intervention choice. Findings from the review will inform health researchers developing cannabis-specific interventions for this population. Survey findings will highlight patients’ preferred characteristics of preventive interventions for cannabis, which can inform future development for young adults with early psychosis who use cannabis.