Patients with psoriasis have a higher risk of schizophrenia: A systematic review and meta-analysis of observational studies

BACKGROUND AND OBJECTIVES: Patients with psoriasis are known to be at a higher risk of several comorbidities, but little is known about their risk of developing schizophrenia. METHODS: A systematic review and meta-analysis of cohort and case–control studies that reported relative risk, hazard ratio, odds ratio (OR), or standardized incidence ratio comparing risk of schizophrenia in patients with psoriasis versus subjects without psoriasis was conducted. Pooled OR and 95% confidence interval were calculated using random-effect, generic inverse-variance methods of DerSimonian and Laird. RESULTS: A total of five studies (one retrospective cohort study and four case–control studies) with more than 6 million participants met the eligibility criteria and were included in this meta-analysis. The pooled OR of schizophrenia in patients with psoriasis versus subjects without psoriasis was 1.41 (95% confidence interval, 1.19–1.66). The statistical heterogeneity was low with an I(2) of 33%. CONCLUSION: This systematic review and meta-analysis demonstrated a significantly increased risk of schizophrenia among patients with psoriasis.