MRI analysis of the cerebellum in bipolar disorder: A pilot study

Since qualitative CT studies have suggested decreased cerebellar size in pa tients with bipolar disorder, we performed a quantitative analysis of the c erebellum in patients with bipolar disorder to determine whether high-resol ution, thin slice magnetic resonance imaging (MRI) morphometry would reveal similar results. Bipolar patients hospitalized for a first manic episode ( n = 16), bipolar patients with prior manic episodes hospitalized for a mani c episode (n = 14), and normal volunteers (n = 15) matched for age, sex, ra ce, and education were recruited and anatomic brain scans were acquired usi ng a Picker 1.5 Tesla MRI scanner. Right and left cerebellar hemisphere vol umes and vermal areas V1 (lobules I-V), V2 (lobules VI-VII), and V3 (lobule s VIII-X) were measured. ANCOVA comparing each ROI, adjusting for race, sex , age, total cerebral volume, and substance abuse duration, revealed a sign ificant group effect for vermal V3 area. Specifically, V3 area was signific antly smaller in multiple-episode patients than in first-episode patients o r healthy volunteers. Number of previous episodes of depression may contrib ute to this finding. These results suggest that cerebellar vermal atrophy m ay be a later neurodegenerative event in patients with bipolar disorder who have had multiple affective episodes. The confounding effects of medicatio ns are considered. (C) 1999 American College of Neuropsychopharmacology. Pu blished by Elsevier Science Inc.