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.