The authors evaluated magnetic resonance imaging (MRI) of deep white matter hyperintensity (DWMH) in 90 adult psychiatric inpatients in whom MRIs were clinically indicated and 25 age-matched, medically healthy controls. Forty-two percent of the psychiatric patients and 12% of the controls had evidence of DWMH on MRI. Both incidence and severity of DWMH were significantly correlated with age in both groups. Even after controlling for age in the psychiatric population, DWMH was significantly associated with hypertension, history of myocardial infarction or angina, abnormal electrocardiogram, and abnormal neurological examinations.