MedWire News: Many women diagnosed with postpartum depression may actually be suffering from bipolar disorder, study findings indicate.
"The results suggest that... misdiagnosis of bipolar disorder in the postpartum period may be quite common," say Dr Verinder Sharma and team from Regional Mental Health Care in London, Ontario, Canada.
Dr Sharma and team studied the medical records of 56 women who were diagnosed with postpartum depression.
The women were also interviewed and underwent a variety of tests to assess their mental health.
Analysis of these test results showed that 54% of these women met the criteria for a diagnosis of bipolar disorder - significantly more than the number of patients who met criteria for a diagnosis of major depressive disorder (46%).
Specifically, 23% of the women had bipolar II disorder, 2% had bipolar I disorder and 29% of the participants had bipolar disorder 'not otherwise specified'.
However, only 10% of the women with bipolar disorder had a previous diagnosis of the condition, and just 27% had a family history of the disorder.
The researchers suggest several reasons why bipolar depression after delivery is misdiagnosed as major depressive disorder.
For example, doctors may not ask their patients about episodes of high mood, "due to the general lack of awareness that the highs are a common occurrence after delivery," they say.
Furthermore, because of the unique circumstance of childbirth, women may not report mood highs, instead focusing on symptoms of depression.
"Our finding that postpartum depression in the majority of patients had a bipolar diathesis may also explain why antidepressants are not particularly effective for prophylaxis [prevention] of postpartum depression," the researchers write in the journal Bipolar Disorders.
They conclude: "The findings have important clinical implications, which include the need for early detection of bipolarity through the use of reliable and valid assessment instruments, and implementation of appropriate prevention and treatment strategies."