Mobile Application-Based Interventions for Cannabis Use in Young Adults With First Episode Psychosis

Psychotic disorders affect approximately 4% of Canadians and have a significant impact on individuals' well-being, their families and social networks, and healthcare systems. The development of psychosis is explained by a complex interplay of genetic and environmental factors, including the use of psychoactive substances. Frequent cannabis use can contribute to the development of psychotic disorders. The prevalence of cannabis use disorder (CUD) in individuals with a first-episode psychosis (FEP) followed in Early Intervention Services (EIS) is 42-53%, well above that of the general population (\~3%). Cannabis use in individuals with psychosis is associated with increased symptom severity, higher rates of relapse and hospitalization, and poor psychosocial functioning. Standardized mobile app-based interventions offer a scalable and accessible solution. Our team developed and piloted CHAMPS (harm reduction) and iCanChange (use reduction/cessation) with favourable results: retention 82% (CHAMPS) and 84-86% (iCC), high satisfaction, and preliminary efficacy signals. The two pilot studies were targeting feasibility, this study is studying efficacy of the two app-based interventions (CHAMPS and iCanChange).

Inclusion Criteria: CHAMPS INTERVENTION * Young adults (18-35 years) with FEP * Cannabis use ≥1 day in the past month * MPS score ≥2, * NOT seeking treatment for cannabis use disorder (CUD). * CUD diagnosis possible but not required. * With a minimum of 2 months of follow-up at an EIS clinic. I CAN CHANGE INTERVENTION * Young adults (18-35 years) with FEP and CUD (DSM-5, moderate to severe) * Seeking to reduce or cease use * With a minimum of 2 months of follow-up at an EIS clinic. Exclusion Criteria: * Pregnancy, breastfeeding, or any medical condition that, in the opinion of the psychiatrist, precludes safe participation or the ability to provide informed consent, * Any disabling, unstable, or acute mental condition that, in the opinion of the psychiatrist, precludes safe participation or the ability to provide informed consent, * Any planned extended absence (pending legal action, surgery, inpatient program) or other reason that, in the opinion of the study team, might prevent completion of the study, * Presence of a substance use disorder that, in the opinion of the psychiatrist, precludes safe participation (e.g., very unstable or severe SUD), * Currently participating in another specific cannabis use-focused intervention.