Bipolar disorder more prevalent and costly than believed

The incidence of bipolar disorder in the general population is considerably higher than earlier studies have indicated, resulting in significantly less productivity and more days lost from work compared to the better known major depressive disorder, according to preliminary findings from a national survey presented today at the Sixth International Conference on Bipolar Disorder.

Another study has found that lithium, one of psychiatry's oldest drugs, may be the most effective solution for preventing suicide in patients with manic-depressive disorder and other types of bipolar disorders. Nearly half of all U.S. suicide deaths each year are in patients with bipolar disorders, in whom the risk is more than 20 times that of the general population.

The new prevalence estimate counts 4.3 percent of adults in the U.S. suffer from a bipolar disorder or "sub-threshold" bipolar disorder, which includes those who don't fit the precise clinical criteria for bipolar disorder but whose symptoms still severely impair their ability to perform daily tasks of living. Previous studies have placed the prevalence at 1 percent.

The findings are included in a new analysis from the National Co-Morbidity Survey Replication (NCS-R), which is the first to examine the prevalence and societal costs of bipolar disorder. As such, the summary of the survey's preliminary results presented by Ronald C. Kessler, Ph.D., professor of health care policy at Harvard Medical School and principal investigator of the NCS-R, bring into sharper focus society's shared burden from bipolar disorder.

Compared to major depressive disorder, bipolar disorder has a significantly greater impact on an individual's ability to go to work or be productive when at work, according to the NCS-R, which included face-to-face interviews with 9,282 U.S. adults. On an annual basis, the mean number of lost days for someone with bipolar disorder is 49.5, versus 31.9 for someone with major depressive disorder. Nationally, bipolar disorder carries a $25,868 billion-a-year price tag, an economic burden not before appreciated, says Dr. Kessler, who believes previous research has over-estimated the societal costs of major depression while underestimating the costs of bipolar disorder.

One significant cost associated with bipolar disorder is suicide, quantifiable in terms of both the loss of human life and its impact on society. Of particular concern is that attempts made by bipolar patients have about a one-in-five chance of being lethal, compared to a one-in-20 attempt-to-suicide rate within the general population.

According to another Harvard researcher, Ross J. Baldessarini, M.D., the number of suicides and attempted suicides, as well as their associated costs, could be reduced significantly in the United States by a return to more widespread use of lithium, as had been more common before the introduction of newer drugs and continues to be standard practice in Europe. The first modern use of lithium to treat mania was more than 55 years ago.

Dr. Baldessarini, a professor of psychiatry at Harvard Medical School, and his team conducted a comprehensive, quantitative review of studies comparing rates of suicides and attempts among patients who were undergoing different treatments, receiving a placebo as part of a clinical trial or receiving no treatment at all.

Patients taking lithium had an 80 to 85 percent lower rate of attempts or completed suicides compared to patients with manic-depressive illness not being treated with lithium, with strikingly consistent findings across a large number of dissimilar studies.

"The effect that bipolar disorder has on individuals, their families, the work place – society as a whole cannot be underestimated. While it's troubling that we are learning the burden is much greater than we even realized, we can take steps to reduce some of the hardship. One approach that may make sense, and which appears could help reduce the burden associated with suicide, is a lithium-based treatment," commented Ellen Frank, Ph.D., professor of psychiatry at the University of Pittsburgh School of Medicine.

Held every two years, the International Conference on Bipolar Disorder is the only venue in the world devoted exclusively to highlighting new research into bipolar disorder. The Sixth Conference is being held June 16 to 18 at the David L. Lawrence Convention Center, located in the heart of downtown Pittsburgh, and is being sponsored by the University of Pittsburgh School of Medicine and Western Psychiatric Institute and Clinic of the University of Pittsburgh Medical Center.