Unsuspected multiple sclerosis in patients with psychiatric disorders: a magnetic resonance imaging study.

Over a 6-year period, 2,783 subjects, consecutively referred from the inpatient unit of a private psychiatric hospital, were evaluated with brain MRI. Twenty-three patients (0.83%) had brain white matter hyperintensities (WMH) that were highly suggestive of multiple sclerosis (MS). The subjects with WMH consistent with MS were most commonly diagnosed with affective illness. They had a significantly longer length of hospital stay during the index admission, a greater number of past psychiatric admissions, a greater prevalence of brain atrophy, and a history of more frequent neurological symptoms and signs than those without these findings.