Perinatal depression: chronobiology, sleep related risk factor and light therapy

Perinatal depression (PND), i.e. minor and major depressive episodes with onset during pregnancy or within 12 months after delivery, are experienced by 10% to20% of females. Untreated pregnancy-related depression increases the risk of preterm birth, low birth weight of the infant, smoking and substance use, shortening of breast-feeding and can have significant negative effect on the emotional and cognitive development of the infants. The pathophysiology of PND is currently unknown and predictors of perinatal depressive symptoms remain poorly understood. Sleep is markedly disturbed during pregnancy and the postpartum period with up to 75% of pregnant women experiencing some form of sleep disruption during pregnancy such as poor sleep quality or sleep continuity and/or specific sleep disorders such as the restless legs syndrome and sleep disordered breathing. Given that in the general population, insomnia has been established as a risk factor for the development of depression, impaired sleep during the perinatal period could be a critical risk factor for the development of PND and structured assessment of sleep and sleep disorders could help identify women at risk for developing depression. Treatment of PND and pregnancy-associated sleep disorders poses a complex problem during the perinatal period due to concerns about adverse effects of treatments on the fetus and later the infant during the breast-feeding period. Psychotherapeutic interventions have been shown to be effective in PND but due to limited availability and logistic issues, such as childcare arrangements, women with PND might be less likely to participate. Bright light treatment is a low cost, home-based treatment with established efficacy for other types of depression. Its efficacy for PND has so far been evaluated in only a very limited number of studies with mixed results that partly may have been due to the universally small sample sizes included. Nevertheless, bright light treatment has been shown to positively affect depression, sleep disorders, circadian synchronization and possibly serotonergic mechanisms implicated in depression, which makes its systematic evaluation for the treatment of PND is especially promising. In summary, PND is a serious concern during the perinatal period and there is a currently an unmet need for the early and reliable identification of females at risk for PND as well as safe treatment options.

These concerns will be directly addressed in the proposed project. Objectives: 1) to systematically explore and characterise risk factors for perinatal depression by prospectively assessing sleep markers, sleep disorders, inflammatory markers and other potential markers during the perinatal period (work package (WP)1), 2) to investigated the effectiveness of light therapy in treating perinatal depression(WP2), and 3) to test whether a short term trial of light therapy during pregnancy can prevent postnatal depression (WP3). Experimental design/Methods: WP1: prospective cohort study following 500 pregnant women during pregnancy up to 12 months after delivery. Genetic, inflammatory, and sleep markers will be assessed during pregnancy. Sleep, circadian rhythm, and mood will be assessed every three months during pregnancy and postpartum with the aim to identify early predictive markers of perinatal depression. WP2: Minor and major depression will be assessing during pregnancy and postpartum and women with depressive symptoms will be randomised (1:1) to 6 week treatment with bright light or placebo dim light to explore effectiveness of bright light therapy during for perinatal depression. WP3: During pregnancy (Month 6), a random sample of subjects will be assigned to 6 weeks bright light therapy to explore whether this treatment can prevent the onset of postpartum depression.

Expected Value of the proposed Project: Perinatal depression is one of the most common complications of child bearing. It can have devastating consequences both for the women and their children and family. This project will improve our understanding of the precursors and risk factors for perinatal depression that can aid in the early identification of women at risk for perinatal depression. Further, results of the planned randomised clinical trial of bright light for perinatal depression will establish whether this easy and safe, at-home treatment that has been documented to be effective in treating depression outside pregnancy, can be a viable treatment options during the perinatal period. Finally, given its serious, long-term consequences it would be preferable to prevent postpartum depression rather than treat it once it is established and we will explore whether light therapy after delivery can prevent the onset of postpartum depression. In summary, the proposed project is expected to significantly contribute to improved care and treatment of women during and after pregnancy and ultimately to the long-term well being of mothers, children and family.