Physical comorbidities increase the risk of psychiatric comorbidity in multiple sclerosis

Background Risk factors for psychiatric comorbidity in multiple sclerosis (MS) are poorly understood. Objective We evaluated the association between physical comorbidity and incident depression, anxiety disorder, and bipolar disorder in a MS population relative to a matched general population cohort. Methods Using population‐based administrative data from Alberta, Canada we identified 9624 persons with MS, and 41,194 matches. Using validated case definitions, we estimated the incidence of depression, anxiety disorder, and bipolar disorder, and their association with physical comorbidities using Cox regression, adjusting for age, sex, socioeconomic status, and index year. Results In both populations, men had a lower risk of depression and anxiety disorders than women, as did individuals who were ≥45 years versus