Seasonality linked to premenstrual symptoms in bipolar disorder
MedWire News: Seasonality is significantly associated with premenstrual syndrome (PMS) in women with bipolar disorder, particularly those with bipolar II disorder (BD II), researchers report.
"Seasonal affective disorder (SAD) and PMS are cyclic forms of clinical conditions in which characteristic mood symptoms recur and remit in a rhythmic pattern," observe Kyung Sue Hong (Samsung Medical Center, Seoul, Korea) and team.
They add: "Although SAD and PMS are known to be frequently found in patients with mood disorders including bipolar, whether or not general traits for seasonality and premenstrual distress are related to bipolar disorder independent of its affective episodes has yet to be determined. In addition, the association between these two traits has never been investigated with respect to bipolar disorder."
To address these issues, the researchers recruited 61 women with bipolar disorder, aged an average of 33.2 years, and 122 age-matched mentally healthy women (controls). Of the women with bipolar disorder, 31 had BD II and 30 had bipolar I disorder (BD I).
The participants were assessed for seasonality - the tendency to experience seasonal variations in mood, behavior, and vegetative functions - using the Seasonal Pattern Assessment Questionnaire (SPAQ), and for lifetime PMS using the Premenstrual Symptoms Screening Tool.
The researchers found that BD II and BD I patients had significantly higher levels of seasonality than controls, with mean global SPAQ scores of 9.2 and 7.8 versus 5.0, respectively.
The prevalence of moderate-to-severe PMS was significantly higher in BD II patients than in BD I patients and controls, at 51.6% versus 23.3% and 19.7%, respectively.
Combining the BD II and BD I groups, the researchers found a significant positive association between seasonality and PMS in both bipolar patients and controls, although the association was strongest in the bipolar patients.
Hong and team conclude in the Journal of Affective Disorders: "The results suggested that female patients with bipolar disorder experience seasonal and premenstrual changes in mood and behavior regardless of their mood episodes, and traits of seasonality and PMS are associated with each other."
They add: "A common biological mechanism of these two cyclic conditions may be involved in the development of the cyclicity of bipolar disorder."
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By Mark Cowen