June 1, 2010 (New Orleans) -- About one in three people diagnosed with major depression may actually have bipolar disorder, researchers report.
Five characteristics, including extreme mood swings and psychiatric symptoms at a young age, may help pinpoint which patients actually have bipolar disorder, they say.
Bipolar disorder covers a spectrum of disorders in which patients may be sad and down one day and feeling on top of the world, hyperactive, creative, and grandiose the next.
The extreme mood swings may be more or less frequent and more or less severe, says study head Charles Bowden, MD, of the University of Texas Health Science Center in San Antonio. Bowden has consulted for Sanofi-Aventis, which funded the study.
"As a result, bipolar disorder can be difficult to diagnose, even by experienced psychiatrists," he tells WebMD.
Recent studies suggest as many as 40% of patients receive another diagnosis first and that it can take years before they're correctly diagnosed, Swanson says. Many are diagnosed with major depression, resulting in inappropriate use of antidepressants, he says.
Not only do antidepressants fail to help, "but patients can get worse, their mood can become more unstable, and some even get more manic," says Donald Hilty, MD, co-chair of the committee that chose which studies to highlight at the meeting and professor of psychiatry at the University of California, Davis.
These patients should be on a mood-stabilizing drug, he tells WebMD.
The current study involved 5,635 patients with major depression from 18 countries in Europe, Asia, and North Africa.
The researchers sought to determine which patients fit the criteria for bipolar depression using various tools, and see which factors best predicted a diagnosis of bipolar disorder.