Bipolar, pregnancy link sought

Western professor Verinder Sharma knows the subject needs clarity. So he and his team went looking for it.

Researchers understand bipolar disease is most common among young women, especially at the height of their reproductive years. Building off that, a handful of recent – and somewhat contested – studies have eyed pregnancy’s potential positive impact on controlling the disease.

Bipolar disorder – characterized by depression, hypomania or mania – can lead to suicide, infanticide and increased risk for psychiatric hospitalization during the postpartum period. During pregnancy, though, the impact remains unclear.

Through a comprehensive literature review, Sharma, a Lawson Health Research Institute scientist, and his team sought to define clearly what scientists already knew about bipolar disorder during pregnancy, and where they should look next.

The study, funded by the Ontario Mental Health Foundation, was published online last month in The Journal of Clinical Psychiatry.

Despite contradictory findings, Sharma suggests pregnancy could have a positive impact on bipolar disorder. Throughout the literature, bipolar II disorder was either uncommon or in remission during pregnancy, and women already diagnosed had fewer and shorter episodes while pregnant. Pregnant women also had a lower risk of any other mood disorder than non-pregnant women.

 “There is no period in a woman’s life when the risk of relapse of bipolar disorder is as high as in the postpartum period. This is in sharp contrast to pregnancy, when women may experience an improvement in their symptoms,” Sharma said. “If we fail to understand the effect of pregnancy on bipolar disorder, we will fail to understand bipolar disorder.”

However, the impact of mood stabilizer medications has complicated much of the existing data, with bipolar disorder often misdiagnosed as depression, and prescribed antidepressants as treatment. These medications are known to make bipolar symptoms worse.

“Misdiagnosis are unfortunately are very common,” Sharma said, more so with bipolar II disorder where the depressive episodes (lows) can be more frequent and intense than the manic episodes (high).

“There are some people who may assume that treatment is always better than no treatment for bipolar, but that is not necessarily true, because if you use the wrong treatment, actually you may be making it worse.”

Similarly, many women taking mood stabilizers discontinue their prescriptions to avoid potential side effects on their unborn babies and this rapid break appears to provoke bipolar episodes.

These circumstances have made it challenging for scientists to separate the impact of the drugs from the impact of the disorder.

As far as next steps, Sharma called for large, multicentre studies that specifically address the natural course of the disorder.

“We really need to look at all the underlying factors and be able to make a clearer distinction,” he said.