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Study identifies predictors of bipolar disorder risk

May 22, 2006

A new study presented today at the 159th Annual Scientific Meeting of the American Psychiatric Association (APA) in Toronto, Canada identified five predictors for bipolar disorder risk in patients who have been unsuccessfully treated with antidepressants. Researchers concluded that significant risk factors of bipolar disorder among patients already diagnosed with major depression were anxiety, feelings of people being unfriendly, family history of bipolar disorder, a recent diagnosis of depression, and legal problems.

The study also found that forty-three percent of patients who responded positively to any three risk factors, screened positive for bipolar disorder using the Mood Disorder Questionnaire (MDQ), a validated screener for bipolar disorder. In addition, one-third of patients whose medication for their depression was not right for them and that they had been told by a doctor they had anxiety and felt people were unfriendly toward them, screened positive for bipolar disorder, using the MDQ.

Based on these findings, a brief assessment tool was derived that can be used to identify bipolar disorder risk.

"Bipolar depression may be difficult for both patients and doctors to identify because the symptoms are often confused with major depression," said Joseph R. Calabrese, M.D., Professor of Psychiatry, Case Western Reserve University and Director, Mood Disorders Program, University Hospitals of Cleveland. "Given the difficulty of diagnosing bipolar disorder, the five predictors identified in this study may help physicians better assess a patient's risk for bipolar disorder, which could lead to more effective treatment."

The study findings coincide with previous research that suggests nearly half of all patients who have bipolar disorder will first be diagnosed with major depression. Inappropriate treatment due to misdiagnosis can have a harmful effect on patients potentially making the illness harder to treat; antidepressants alone have been shown to induce mania or hypomania (a mild form of mania) in some patients with bipolar depression. Furthermore, people with untreated bipolar disorder can experience a greater frequency of manic and depressive episodes, causing significant disruption in their personal and professional lives.

"Many people with bipolar disorder face up to ten years of coping with symptoms before getting an accurate diagnosis," said Karl Ackerman, President of the Manic-Depressive and Depressive Association of Boston. "For me, it was twelve years. Looking back, I realize the anxiety I experienced along with my depression could have been another sign of bipolar disorder. These predictors can be useful for patients who are dealing with depression that isn't helped by medication."

"It's important for people who are suffering from depression to talk to their doctors about other experiences and symptoms over their lifetime - especially times when they were feeling really well," said Gary Sachs, MD, Associate Professor of Psychiatry, Harvard Medical School and Director, Bipolar Disorder Clinic and Research Program, Massachusetts General Hospital. "Many patients with bipolar disorder go too long without a correct diagnosis. This can mean years lost to an illness that can be successfully managed when correctly diagnosed and treated. The predictors identified in this study may help physicians and patients identify depression associated with bipolar disorder rather than unipolar mood disorder."

Study Design

The study was designed to identify predictors of bipolar disorder risk among patients treated for major depression. Psychiatrists from community and private practice clinic settings randomly selected patients who were unsuccessfully treated with antidepressants. Patients self-reported demographics, family history, co-morbid health status, alcohol/drug use, legal problems, and current depression using the Centers for Epidemiologic Studies Depression (CES-D) scale. Screening for bipolar disorder was self-reported using the Mood Disorder Questionnaire (MDQ), a validated screening instrument for Bipolar I and II disorders.

Of the 602 patients enrolled in the study, 18.6% screened positive for bipolar disorder using the MDQ (MDQ+). Researchers identified five significant variables associated with bipolar disorder risk: the CESD item "people were unfriendly" (p<.001), co-morbid anxiety (p<.002), depression diagnosis within five years (p<.001), family history of bipolar disorder (p<.010), and legal problems (p<.026).

For patients with no risk factors (n=41), 2.4% screened positive for bipolar disorder using the MDQ. For patients endorsing "people were unfriendly" (n=103), 31.1% screened positive for bipolar disorder; adding co-morbid anxiety (n=82) the percent of MDQ+ patients increased to 35.4%; adding recent depression onset (n=17) increased MDQ+ rate to 41.2%; adding family history (n=4) increased MDQ+ rate to 75%; one hundred percent of patients endorsing all five factors (n=3) were MDQ+. Forty-three percent of patients who responded positively to any three risk factors, screened positive for bipolar disorder using the MDQ.

Researchers concluded that over one-third of patients who potentially experienced projection or rejection sensitivity determined by the endorsement of the CES-D item "people were unfriendly" as well as co-morbid anxiety were at risk for bipolar disorder. These two clinical features and recent depression onset, bipolar disorder family history and legal problems may prove useful indicators of bipolar disorder risk among patients with major depression who have been unsuccessfully treated with antidepressants.

Cohn & Wolfe Healthcare