The association between ankylosing spondylitis and psychiatric disorders: Insights from a population based cross-sectional database

Background: Ankylosing spondylitis (AS) is an inflammatory rheumatic disease involving the axial skeleton ultimately resulting in physical disability and psychological sequalae. The current study aims to evaluate the link between AS and psychiatric disorders, and to investigate the impact of different disease modifying drugs on such link. Methods: A large retrospective, population-based, cross-sectional study utilizing the Clalit-Health-Service (CHS) database was conducted on 5825 AS patients and 25,984 age- and sex-matched control individuals. The prevalence of psychiatric morbidity was compared between AS patients and age- and gender-matched controls. Predictors for psychiatric disorders in AS patients were also investigated. Results: The prevalence of psychiatric morbidity was higher in AS patients compared to controls (13.8 % vs. 9.8 %, p < 0.001). Similarly, major depression was positively associated with AS (OR 1.60, 95 % CI 1.43–1.79, p < 0.001), however, schizophrenia was negatively associated with AS (OR 0.60, 95 % CI 0.42–0.89, p < 0.011). Conventional DMARDs (cDMARDs) and anti-TNF used for management of AS were not shown to be predictors for psychiatric illnesses in AS patients. Conclusions: Patients with AS are at a higher risk of developing psychiatric disorders, with increased risk of depression and lower risk of schizophrenia. cDMARDs and TNF-inhibitors are not predictors of psychiatric disorders in AS patients.