Mania after brain injury. A controlled study of causative factors.

Eleven patients who developed manic syndromes after brain injury (secondary mania) were studied. Six patients had depressive episodes before mania and five had a definite or possible family history of affective disorder. Eight had lesions involving limbic areas, and nine had right hemisphere involvement. In addition to focal brain injury, mean values for bifrontal and third ventricle/brain ratios of manic patients were significantly increased when compared with non-manic patients who had lesions matched for cause, location, volume, and time since injury. Results indicate that the confluence of either anterior subcortical atrophy and a focal lesion of a limbic or limbic-connected region of the right hemisphere, or genetic loading and a limbic-connected right hemisphere lesion may account for the rare occurrence and specific factors necessary to produce secondary mania.