PITTSBURGH — Misdiagnosis of bipolar disorder in the postpartum period may be quite common, Dr. Verinder Sharma and his associates said in a poster presentation at the Seventh International Conference on Bipolar Disorder.
Among 56 women consecutively referred for evaluation of postpartum depression, structured instruments—including the Structured Clinical Interview for DSM-IV—revealed that more than half actually had bipolar disorder. Of those 30 women, 13 had bipolar I disorder, 1 had bipolar II disorder, and 16 had bipolar disorder not otherwise specified, reported Dr. Sharma, a gynecologic psychiatrist at Regional Mental Health Care, London, Ont.
“When people think about postpartum [mental] disorders, they're thinking about the blues, about depression, or psychosis. How many are thinking about postpartum hypomania? There isn't the awareness,” he said in an interview at the meeting, sponsored by the University of Pittsburgh.
Misdiagnosis of bipolar disorder as unipolar depression is a well-documented phenomenon in the psychiatric literature, and a couple of studies have now shown that episodes of hypomania occur in approximately 15% of all postpartum women. Indeed, among women at increased genetic risk, the combination of hormonal changes and sleep deprivation can serve as triggers for a hypomanic or manic episode. “There is no time in a woman's life when the risk of a hypomanic episode is [as] high as the postpartum period,” Dr. Sharma remarked.
Clinically, it may be difficult to distinguish normal feelings of elation from those of abnormal mood elevation. Women should be asked if they have felt as if their minds were racing, whether they have increased energy and increased levels of goal-directed activity—cleaning the house, for example—despite a lack of sleep, or if they have been spending more money than usual.
Anecdotally, Dr. Sharma said, some patients have confided to him about having intense sexual desire during these episodes. “We don't typically elicit these symptoms, but I think they are there,” he commented.
The Mood Disorder Questionnaire has not been validated for the postpartum period, but it can be a valuable assessment tool. There is a caveat: The DSM-IV requires a distinct 4-day period of persistently elevated, expansive, or irritable mood among the diagnostic criteria for hypomania, but in Dr. Sharma's experience those periods tend to be shorter among postpartum women.
“In actual clinical practice, around 2 days is what I'm seeing,” he explained.
It is important to ask women about a family history of mood disorders, particularly of depression, mania, or psychosis. A positive family history for bipolar disorder or psychosis places a woman at extremely high risk for bipolarity during the postpartum period.
Dr. Sharma's study also revealed that bipolarity is not the only psychiatric problem that tends to be missed among postpartum women: Comorbid anxiety disorder also was found in 16 of the 30 women with bipolar disorder (53%) and in 11 of the 26 women (42%) with major depressive disorder. And, while none of the women were found to have current substance abuse problems, a lifetime history of substance abuse disorder was found in five patients in the bipolar group (16%) and four of the unipolar depressed patients (15%).
“[Postpartum] women should also be screened for anxiety disorders and substance use disorders,” Dr. Sharma said.