Interviews with members of more than 5,000 representative U.S. households as part of the National Comorbidity Survey Replication found that nearly 40 percent of those with major depressive disorder may actually have subthreshold hypomania, defined as a discrete period of increased energy, activity, and euphoria or irritability that is not related to impairment in daily activities.
Hypomania is a less disruptive form of mania that lacks psychotic symptoms. The majority of patients with bipolar disorder experience hypomania, rather than mania. Recognition of subthreshold hypomania, or hypomanic symptoms below the threshold for bipolar disorder, would have implications for the diagnosis and treatment of major depression.
Among those with subthreshold hypomania, family history of mania was just as common as it was among people with threshold mania. In addition, compared to those with depression alone, those who had depression with subthreshold hypomania tended to have an earlier onset of mood disorder, higher rates of anxiety and substance abuse, and more depressive episodes. Other research has shown that young people with subthreshold hypomania are more likely to develop bipolar disorder over time.
The findings provide key information for evaluating diagnostic criteria for mood disorders and have important implications for promoting appropriate treatment for individuals with bipolar spectrum disorders. Author Kathleen Merikangas, Ph.D., states, “Recognition of hypomania among people with major depression is important in determining the future risk for the development of bipolar disorder, and should be considered in treatment decisions among people with major depression. The increased rate of suicide attempts is of particular concern.”
The study will appear on August 16 at AJP in Advance, the online advance edition of The American Journal of Psychiatry (AJP), the official journal of the American Psychiatric Association. The National Comorbidity Survey Replication was supported by the National Institute of Mental Health (NIMH), National Institute of Drug Abuse, Substance Abuse and Mental Health Services Administration, Robert Wood Johnson Foundation, and John W. Alden Trust. Manuscript preparation was supported by NIMH and the French National Center for Scientific Research.