Cannabis use is a recognized risk factor for psychosis, yet the psychological mechanisms mediating this relationship remain incompletely understood. This 24-month prospective observational study investigated the role of hopelessness and depression in the development, maintenance, and outcomes of cannabis-induced first-episode psychosis (CIP). Participants (N = 72) with CIP were assessed at baseline and followed up at 6, 12, and 24 months. Hopelessness (Beck Hopelessness Scale), depressive symptoms (Calgary Depression Scale for Schizophrenia), psychotic symptoms (PANSS), and cannabis use patterns were evaluated. Both hopelessness (β = 0.30, p < 0.001) and depression (β = 0.34, p < 0.001) independently predicted psychotic symptom severity after controlling for confounding variables. Mediation analyses revealed that hopelessness and depression partially mediated the relationship between cannabis use and persistent psychotic symptoms, accounting for 31% and 35% of the total effect, respectively. Continued cannabis use during follow-up was associated with increased hopelessness and depression, which predicted worse clinical outcomes. The combination of high hopelessness, clinically significant depression, and continued cannabis use conferred a particularly elevated risk for relapse (HR = 4.32, 95% CI [2.41, 7.75]). These findings highlight the importance of assessing and addressing hopelessness and depression in CIP patients and suggest that these psychological factors represent potentially modifiable treatment targets that may improve outcomes in this vulnerable population.
Keywords: Cannabis; Depression; First-episode psychosis; Hopelessness; Treatment outcomes.
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