The paper determined whether bipolar I patients could be sub-grouped into unipolar manics & those with mania plus depression. Family histories, previous hospitalizations, age of onset & previous suicide attempts were compared. Suicide attempts were related to incidence & severity of depression. Lithium was found to be an effective prophylactic agent. Unipolar mania appears to be a subgroup of bipolar I illness, evidence does not support it as a separate entity. (MRE)