Risk of Schizophrenia in Patients with Psoriasis: A Systematic Review and Meta-Analysis

Background. Several studies have shown that psoriasis patients have a higher prevalence rate of schizophrenia, but none has thoroughly examined this association across different ages and genders. Thus, our systematic review and meta-analysis aims to combine all available evidence and evaluate the risk of schizophrenia in psoriasis patients. Methods. Two independent investigators extracted published studies from PubMed, Embase, Medline, and Web of Science databases from inception until May 2023 and screened 160 articles for eligibility. We included 8 studies in this meta-analysis. A random-effects model was employed to estimate the pooled odds ratio (OR) and 95% confidence interval (CI) for schizophrenia in patients with psoriasis. The study protocol is registered with PROSPERO, number CRD42023428576. Results. A total of eight studies with 889,747,79 participants met the eligibility criteria. The pooled OR of psoriasis in patients with schizophrenia versus subjects without schizophrenia was 1.66 (95% CI: [1.20, 2.29]) with a significant level of heterogeneity ( $I^2$ = 97%). Specifically, the OR for psoriasis in children with schizophrenia was 12.90 (95% CI: [1.97, 84.64]), with an $I^2$ combined value of 98% and psoriasis in adults with schizophrenia 2.57 (95% CI: [1.44, 4.58]), with an $I^2$ combined value of 61.3%. The combined OR for all age groups was 5.27 (95% CI: [3.02, 9.19]). Additionally, we found that the OR value for psoriasis in females with schizophrenia was 1.74 (95% CI: [1.74, 2.11]), with an $I^2$ combined value of 59%. For male patients, the OR value was 1.58 (95% CI: [1.25, 2.01]), with an $I^2$ combined value of 77%. Conclusions. Our study shows an increased risk of schizophrenia in people with psoriasis. We demonstrated a significantly increased risk of schizophrenia among children with psoriasis and found that females with psoriasis were more likely to have schizophrenia than men with psoriasis under the same conditions.