Hidradenitis suppurativa and schizophrenia: a nationwide cohort study

Background: Hidradenitis suppurativa (HS) is a chronic, debilitating, dermatological disease that causes substantial psychosocial impediments with increased suicidal risk. Yet data on psychiatric comorbidity in HS have not been sufficiently elucidated in population-based studies. The current study sought to investigate the association between HS and schizophrenia, a major psychiatric disease, in a nationwide population-based study in Israel. Methods: Data mining was performed on the database of Clalit Health Services (CHS), the largest managed healthcare company in Israel. Patients diagnosed with HS (n = 4191) were examined and compared to age- and sex-matched controls (n = 20 941). The association between HS and schizophrenia was assessed via multivariate binary logistic regression, adjusting for demographic factors and smoking status. Results: The analysis revealed a tenfold increase in the prevalence of schizophrenia in HS patients compared to controls (1.4% and 0.4%, respectively, P < 0.001). In multivariate analysis, HS was found to be associated with schizophrenia (OR 1.44, 95% CI 1.01–2.07, P < 0.05). Conclusions: Hidradenitis suppurativa is associated with schizophrenia. Screening for severe mental illness during the assessment of patients with HS is of great importance, as comorbid psychiatric disorders may affect treatment outcomes.