Silent cerebral infarctions in patients with late-onset mania

Previously we have studied the relationship between senile depression and silent cerebral infarctions (SCIs). The goal of this study was to clarify the relationship between late-onset mania and SCIs using MR imaging.

Twenty manic patients who developed a bipolar disorder after 50 years of age (late-onset mania) were selected prospectively. These patients were compared with 20 age- and sex-matched patients who developed an affective disorder while younger than 50 years of age (early-onset affective disorder) and with 20 patients who developed major depression after 50 years of age (late-onset major depression). Patients with focal neurological symptoms were excluded from the study. All patients underwent MR imaging to assess the incidence of SCIs. Patients diagnosed with SCIs were subclassified according to whether the infarction type was perforating, cortical, or mixed.

The incidence of SCIs in patients with late-onset mania was 65.0%; this incidence was significantly higher than that of patients with early-onset affective disorders (P < .05). The incidence of the mixed type of SCI was 50.0% in patients with late-onset mania; this was significantly higher than that in patients with late-onset major depression (P < .05).

Our findings suggest that approximately half of the cases of late-onset mania might be secondary mania related to SCIs. Because the mixed type of SCI is more prevalent in the patients with late-onset mania than in those with late-onset major depression, mania may be associated with the larger areas of brain damage and hence may be a more serious form of affective illness than major depression.