Background: Structural brain imaging is assumed to be a key method to elucidate the underlying neuropathology of bipolar disorder. However, magnetic resonance imaging studies using region of interest analysis and voxel-based morphometry (VBM) revealed quite inconsistent findings. Hence, there is no clear evidence so far for core regions of cortical or subcortical structural abnormalities in bipolar disorder. The aim of this study was to investigate grey and white matter volumes in a large sample of patients with bipolar I disorder.
Methods: Thirty-five patients with bipolar I disorder and 32 healthy controls matched with respect to gender, handedness and education participated in the study. MRI scanning was performed and an optimized VBM analysis was conducted.
Results: We could not observe any significant differences of grey or white matter volumes between patients with bipolar disorder and healthy control subjects. Additional analyses did not reveal significant correlations between grey or white matter volume with number of manic or depressive episodes, duration of illness, existence of psychotic symptoms, and treatment with lithium or antipsychotics.
Conclusions: With this VBM study we were not able to identify core regions of structural abnormalities in bipolar disorder.