Unipolar and Bipolar Depression Have Subtle Differences, Says Study

New research suggests that depression in patients with bipolar disorder may be slightly different from depression in patients with unipolar depression.

Lauren Weinstock and colleagues from Warren Alpert Medical School at Brown University and Butler Hospital in Providence, Rhode Island, studied data from interviews of 13,058 people who participated in the National Epidemiological Survey on Alcohol and Related Conditions. Of these, 1,154 reported a history of depression in the context of bipolar disorder and 11,904 reported a history of unipolar depression.

Analysis of the data revealed that, while both groups experienced few differences in the type of depression symptoms they had, the group with bipolar disorder tended to experience suicidal thoughts and psychomotor disturbance more frequently and at a lower severity of depression than those with unipolar depression. The researchers further found that unipolar patients more frequently experienced fatigue at moderate - but not low or high - levels of depression than the bipolar patients did.

The researchers suggest that these subtle differences in symptom presentation may be helpful in distinguishing between these two conditions in depressed patients,

The study appears in the April 2009 issue of Bipolar Disorders.