Reduction of cingulate gray matter density in poor outcome bipolar illness

Structural brain abnormalities are associated with poor outcome unipolar depressive disorder. Gray matter density can be assessed with an automated, operator independent analysis (SPM99). We thus compared 11 poor outcome bipolar patients with 15 age-, sex- and IQ-matched healthy volunteers with a standard neuropsychological examination and an Elscint 2.0 Tesla MRI scanner. At the time of examination, patients were neither hypomanic nor significantly depressed, but were significantly impaired on the McGlashan scale. Their memory function was characterized by reduced performance in the California verbal learning and digit-symbol substitution tests. Statistical parametric mapping revealed abnormal gray matter density, mainly in fronto-limbic cortex, but particularly widespread in cingulate cortex. Although causality of these changes is difficult to resolve, the results offer useful insights into the neural correlates of severe bipolar disorder.