The burden of mental comorbidity in multiple sclerosis: frequent, underdiagnosed, and undertreated

Background Mental comorbidity is common in multiple sclerosis (MS), but some studies suggest that mental comorbidity may be underrecognized and undertreated. Objective Using the North American Research Committee on MS Registry, we assessed the frequency of mental comorbidities in MS and sociodemographic characteristics associated with diagnosis and treatment of depression. Methods We queried participants regarding depression, anxiety, bipolar disorder, and schizophrenia. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale (CESD); a score ≥21 indicated probable major depression. Results Mental comorbidity affected 4264 (48%) responders; depression most frequently (4012, 46%). Among participants not reporting mental comorbidity, 751 (16.2%) had CESD scores ≥21 suggesting undiagnosed depression. Lower socioeconomic status was associated with increased odds of depression (Income $15,000–30,000 vs >$100,000 OR 1.34; 1.11–1.62), undiagnosed depression (Income $15,000–30,000 vs >$100,000 OR 1.52; 1.08–2.13), and untreated depression (<high school vs postgraduate degree OR 3.13; 1.65–5.99). Conclusions Mental comorbidity remains underdiagnosed and undertreated in MS. Patients of lower socioeconomic status bear a disproportionate share of the burden of depression.