Prevalence of schizophrenia spectrum and bipolar disorder among patients with cannabis induced psychosis: a systematic review and meta-analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational cohort studies
PubMed 41664079 · doi:10.1186/s12888-025-07382-2
What was done
Authors systematically reviewed Medline, Embase, Web of Science, Google Scholar, and PsycINFO through January 1, 2025, for studies reporting on patients with cannabis-induced psychosis and subsequent diagnoses of schizophrenia spectrum disorder, bipolar disorder, or both. Quality was assessed using a modified Newcastle-Ottawa scale. Random-effects meta-analyses and meta-regressions were conducted to calculate pooled prevalence estimates.
What was found
Across 13 included studies with 7,515 participants reporting 16 outcomes of interest: - 20% (95% CI: 15.8–29.5%) of patients with cannabis-induced psychosis later received a schizophrenia spectrum disorder diagnosis. - 5% (95% CI: 2.7–6.9%) later received a bipolar disorder diagnosis. - 63% (95% CI: 26.8–90.5%) received an unspecified (both) diagnosis. - Patients were 76% less likely to develop bipolar disorder compared to schizophrenia spectrum disorder. - Later diagnosis of an unspecified disorder showed an ARR of 2.52 (95% CI: 1.03–6.15) compared to schizophrenia spectrum disorder alone.
Why it matters
This meta-analysis provides pooled risk estimates for long-term psychiatric outcomes after cannabis-induced psychosis, showing that roughly one in five patients later transition to schizophrenia spectrum disorders and one in twenty to bipolar disorder.
Limits
The underlying evidence consists of observational cohorts with variable follow-up durations and potential diagnostic misclassification. Confounding factors such as baseline subclinical psychopathology and continued substance use were not described in the abstract. The estimate for unspecified diagnoses showed extremely wide confidence intervals (26.8% to 90.5%), reflecting high heterogeneity.
Cited by
- supports Cannabis use, whether high-potency or low-potency, can trigger persistent psychotic episodes from which individuals do not recover, as supported by scientific data.