Patients with primary major depression (N = 372) were followed for 2
years to determine the prognostic importance of past manic or hypomanic
episodes. While bipolar I and bipolar II patients were more likely to
relapse and bipolar I patients were more likely to attempt suicide, these
patients resembled nonbipolar depressed patients in likelihood of recovery
and psychosocial impairment in various areas. Compared to nonbipolar
patients, those with bipolar I depression were much more likely to develop
mania, while bipolar II patients were more likely to develop hypomania.
Cycling during the index episode predicted a relatively low likelihood of
recovery for bipolar I patients but had no apparent prognostic significance
for patients with bipolar II illness.