Depression, anxiety co-occur in bipolar disorder patients following mania

Adults with bipolar disorder are just as likely to develop anxiety as depression following an episode of mania, according to data from a national survey of more than 34,000 adults. This finding, published today in Molecular Psychiatry, may expand our understanding of bipolar disorder to include anxiety.

An estimated 5.7 million Americans have bipolar disorder, a serious mental illness that has been characterized by recurrent periods of mania and depression. Because mania, which involves having an elevated or irritable mood, and depression are mood disturbances, bipolar disorder is considered a type of mood disorder.

Study participants were interviewed to determine the incidence of manic episodes. A second interview was conducted three years later to determine the subsequent incidence of depression or anxiety. Participants with mania had an approximately equal risk of developing depression (odds ratio of 1.7) or anxiety (odds ratio of 1.8). Both conditions were significantly more common among participants with than without mania. In addition, participants with depression had a significantly higher risk of developing mania (odds ratio of 2.2) or anxiety (odds ratio of 1.7) compared to those without depression.

Results of the report align with earlier research demonstrating that depression and anxiety commonly co-occur, and with twin studies indicating that depression and a common form of anxiety known as generalized anxiety disorder behave virtually as the same genetic condition. The new findings extend the close connection between depression and anxiety to individuals with bipolar disorder who have experienced episodes of mania.

"Although it has long been widely assumed that bipolar disorder represents repeated episodes of mania and depression as poles along a single continuum of mood, the clinical reality is often far more complex," said Mark Olfson, MD, MPH, professor of psychiatry at Columbia University Medical Center, research psychiatrist at New York State Psychiatric Institute, and lead author of the report. "The link between mania and anxiety suggests that patients whose main symptom is anxiety should be carefully assessed for a history of mania before starting treatment."

A broader clinical definition of bipolar disorder that includes episodes of mania along with anxiety or depression might lead to earlier identification of individuals with bipolar disorder and different approaches to treatment.

"For years, we may have missed opportunities to evaluate the effects of treatments for bipolar disorder on anxiety," said Dr. Olfson. "The results of our study suggest that researchers should begin to ask whether, and to what extent, treatments for bipolar disorder relieve anxiety as well as mania and depression."