A LONGITUDINAL INVESTIGATION OF CIRCADIAN RHYTHMS AND SLEEP DISTURBANCES ACROSS THE PERINATAL PERIOD IN WOMEN AT LOW AND HIGH RISK OF POSTPARTUM DEPRESSION

Abstract

Postpartum depression (PPD) remains a serious mood disorder without a known etiology. PPD has a prevalence of 7-15% in the general population. Women with a history of a mood disorder are at an even higher risk for the development of PPD. Work over the last few decades has established a strong association between circadian rhythm and sleep disturbances and mood disorders, such as Major Depressive Disorder (MDD) and Bipolar Disorder (BD). Despite the breadth of evidence associating circadian rhythm disruption and depressive mood episodes, literature establishing a connection between circadian rhythms and changes in mood across the perinatal period is lacking. The work outlined in this thesis aimed to address this gap by examining the association between circadian rhythm and sleep disturbances across the perinatal period and their association with changes in mood in women at high and low risk of PPD development. A total of 87 women were studied, 45 healthy controls and 42 women with a mood history. Women were interviewed during the third trimester of pregnancy and between six to twelve weeks postpartum. Sleep and circadian rhythms were measured using both subjectively with self-reported questionnaires and objectively with actigraphy. Our results show that women at high and low risk showed higher disruption differ in subjective circadian rhythmicity, as well as in both subjective and objective parameters of sleep. Specifically, women at high risk for postpartum were found to have lower sleep efficiency, as measured by actigraphy, in the postpartum. In addition, subjective and objective parameters of sleep and circadian rhythms are associated with changes in depressive symptoms across the perinatal period. Our findings suggest that stabilizing circadian rhythms and improving sleep quality throughout the perinatal period can prevent postpartum mood worsening, particularly for those women at greatest risk.