Cerebellar blood volume in bipolar patients correlates with medication

Cerebellar abnormalities, including decreased tissue volume, have been implicated in the pathophysiology of bipolar disorder. Relatively little research has focused on blood flow in the cerebellum of patients with bipolar disorder. Furthermore, the significance of metabolic changes in the brains of psychiatric patients may be confounded by the effects of various pharmacotherapies. Having previously found differences in cerebellar blood volume in patients with bipolar disorder compared to healthy control subjects, this study examined whether some variability in the patient population may be an effect of medication.

In this study, we have examined the association between medication status and cerebellar blood volume. Thirteen healthy comparison subjects and 21 bipolar patients underwent dynamic susceptibility contrast magnetic resonance imaging. Nine cerebellar regions were identified, and the absolute cerebellar blood volume data from each was compared to medication status measures.

Patients on conventional antipsychotics had the lowest mean absolute blood volume measures for all cerebellar regions, whereas those on atypical antipsychotics had the highest blood volume measures. Comparison subjects had cerebellar blood volume measures in the middle, with results closer to subjects in the atypical group.

This evidence suggests that antipsychotic treatment may influence cerebellar blood volume. This effect will be important in considering imaging studies on medicated patients with bipolar disorder and may suggest novel pathways by which these medications affect their changes.