Some treated for depression may actually be bipolar

When Sloan Manning, MD, a family physician from Greensboro, N.C., finished his residency in the late 1980s, selective serotonin reuptake inhibitors had just come on the market, making it possible for him and other primary care physicians to treat depressed patients within their own practices. Not all of his patients got better, however, and he started to investigate whether some had bipolar disorders rather than simple depression.

"The drugs were not working as often as I thought they should, and they were sometimes making people worse," he said.

Dr. Manning has written and lectured on this subject ever since. His efforts are backed by scientific literature saying that a certain percentage of patients diagnosed with depression may actually be bipolar. Most recently, a study published in the July-August Journal of the American Board of Family Practice found that, when screened for this mental illness, more than one in five patients on antidepressants tested positive.

"I'm very concerned that patients are being undertreated or treated improperly," said Robert Hirschfeld, MD, lead author on the paper and chair of psychiatry and behavioral sciences at the University of Texas Medical Branch in Galveston. "Treating bipolar patients with an antidepressant without a mood stabilizer is dangerous."

Also, a study in the Feb. 23 Journal of the American Medical Association found that about one in 10 of a representative sample of patients presenting to a clinic serving a low-income population also tested positive, although it was not reported how many of those were on antidepressants or with what condition they had been diagnosed.

Experts are particularly concerned about undiagnosed bipolar patients who may be on antidepressants. In a worst-case scenario, these patients may experience rapid cycling or a drug-triggered hypomanic episode. At the very least, the treatment may not make them feel any better.

"It's a very hard diagnosis to make," said Neil Kaye, MD, who authored a review of evidence-based medicine on bipolar disorder in the family practice journal and is an assistant clinical professor in the departments of psychiatry and family medicine at Jefferson Medical College in Philadelphia. "But getting it right really is important because you're potentially pouring gas on the fire."

Some experts also suspect that the recent controversy over a possible link between SSRIs and an increased risk of suicide may be a result of the missed cases of bipolar disorder. The Food and Drug Administration announced in July that it would be reviewing data on antidepressant use and suicidal behavior in adults and urged close monitoring of patients when initiating treatment. These recent studies only looked at adults, but the agency previously warned about increased suicide risk in children and adolescents taking these drugs.

"Many of us feel that some of these patients may have possible bipolar disease," said W. Clay Jackson, MD, a family physician from Memphis, Tenn., who has collaborated with Dr. Manning in studying these conditions. "For them, antidepressants create the perfect storm."

The worry that cases of bipolar disorder may be missed, however, is not new, and several studies have shown that even specialists often take years to pin it down. What is new is that, much like the SSRI revolution in the late 1980s and early 1990s that brought depression care into the primary care office, many experts feel that bipolar disorder may be undergoing the same transformation of increasing recognition and improved treatment in this setting.

This change is occurring because new drugs with fewer side effects are coming down the pike.

"Bipolar disorder is kind of where depression was 10 years ago. Most [primary care physicians] refer those patients on," said Susan Louisa Montauk, MD, professor of family medicine at the University of Cincinnati College of Medicine. "We're right in transition, and it's not going to be like that in two years."

Some suggest that the primary care setting may also address some of the challenges of diagnosing bipolar disorder. Many referrals are never followed up, and, even if they are, patients may not be able to see a mental health specialist for more than one or two sessions -- an amount many experts feel is not enough to pin down this diagnosis. Primary care physicians may have more of an opportunity to track patients over time and get a better handle on their range of mental states.

"This is the great advantage of the primary care clinician," said Dr. Jackson. "What we need to learn is how to begin therapy and what to look for when the patients come back."