Regional gray matter changes in bipolar disorder: a voxel-based morphometric study

Objective: To investigate structural abnormalities in bipolar disorder (BD) using optimized voxel-based morphometry (VBM) in closely matched patients and controls, and to examine the relationship of clinical features with regional gray matter (GM) volumes. Methods: Twenty-four patients (six male) aged 19-59 years (mean = 38.21 years, SD = 11.04 years) with DSM-IV bipolar I disorder were compared with 25 control subjects, matched on age, sex, and years of education. VBM analyses were conducted on high-resolution T1-weighted brain magnetic resonance imaging to detect regional GM volume differences between groups, ensuring statistical correlation for age, sex and total intracranial volumes. Within the patient groups, regional GM changes were also investigated. Results: Compared to controls, BD patients had increased GM volume in left parahippocampal gyrus and decreased GM volume in left middle temporal gyrus. Family history, psychotic symptoms and lithium status were associated with regional GM abnormalities in BD patients. Conclusions: This study presents evidence of gray matter volume abnormalities in adults with bipolar I disorder. Regional variation in relation to clinical factors suggests a neurobiological basis for clinical heterogeneity and posits the possibility of trait deficits.