The course of bipolar disorder may be worse in women who have premenstrual symptom exacerbation of their mood symptoms, according to a new prospective one-year study.
Women with bipolar illness are at greater risk of relapse during the postpartum and menopausal transition periods, Dr Rodrigo S. Dias of the University of Sao Paulo Medical School in Brazil and colleagues note in the American Journal of Psychiatry.
There's also evidence that a significant number of women with bipolar illness have worse symptoms premenstrually, the researchers add, but "little is known about the clinical implications of this association."
To investigate, the researchers looked at 191 women with bipolar disorder and premenstrual exacerbation and another 102 women with bipolar illness whose symptoms didn't worsen premenstrually.
The researchers also compared the risk of relapse in the 129 women who were symptom-free at the study's outset, 66 of whom experienced premenstrual symptom exacerbation.
Among the women with premenstrual exacerbation, 73.8% reported having one to three episodes during the one-year study period, compared to 55.9% of the women without premenstrual exacerbation. They were also less likely to have no episodes (24.1% versus 42.2%).
But there was no difference between the two groups in the likelihood of rapid cycling, which occurred in about 2% of the study participants.
Analysis of time to relapse found no difference between the women with and without premenstrual exacerbation when the researchers only looked at syndrome episodes, but there was a difference when they included subsyndromal episodes. With this broader definition, the median time to relapse was 4.5 months for women with premenstrual exacerbation and 8.5 months for women without it.
After adjustment for factors including medication use, use of hormonal contraceptives, and irregular menstrual cycles, the researchers found a hazard ratio of 1.7 for shorter time to relapse among the women with premenstrual exacerbation.
The researchers also found that the women with premenstrual exacerbation had stronger depressive and mood elevation symptoms than the women without premenstrual exacerbation.
"Taken together, these findings suggest that premenstrual exacerbation may be a marker for a more recurrent and symptomatic course of illness among premenopausal women with bipolar disorder," Dr Dias and colleagues write.
They conclude: "The results of this study reinforce the importance of characterising the fluctuations of mood symptoms across the menstrual cycle in women with bipolar disorder.
Premenstrual syndrome in bipolar disorder patients more intense