Genetic-environmental interaction in the postpartum depression

Abstract

Although highly prevalent, Postpartum Depression (PPD) is still under diagnosed and under treated. Its etiology is multifactorial, encompassing psychosocial and biological aspects. Few studies have been carried out so far aiming to evaluate the role of genetic factors in the DPP, with seemly contradictory results. This inconsistency may be due to the fact that it was not taken into account the occurrence of stressful events in life and particularly during pregnancy. Although environmental risk factors, such as prior psychiatric history and low social support during pregnancy are consistently associated consistently with the development of PPD, a significant proportion of women exposed to a lack of social support during pregnancy will not develop PPD. Thus, the risk of PPD in women exposed to environmental adversity can be modified according to the genetic predisposition. This study is aimed at a wide-ranging exploration of several indicators of maternal health including biological, psychological and environmental aspects during pregnancy and their possible associations with the development of PPD, considering a probable biological predisposition for depression, as assessed by two functional polymorphisms: the promoter gene of the serotonin transporter (5HTTPR) and the promoter gene of the corticotropin releasing hormone receptor (CRH1). To our knowledge, few studies have assessed the role of the 5HTTPR in PPD and none evaluated the role of CRH1. The hypotheses to be tested in this study were: a) pregnancy and immediate postpartum events are stressful by themselves and women carrying polymorphisms associated with a greater biological vulnerability to depression would be more likely to develop depressive symptoms during pregnancy and post- childbirth; b) the occurrence of stressful events in the 12 months prior to pregnancy and / or childbirth would be associated with an increased probability of developing depressive symptoms during pregnancy and / or postpartum, in women with higher biological vulnerability to depression, and c) the subjective experience of stress and depressive and anxiety symptoms during pregnancy would be associated with greater likelihood of developing PPD in women with a greater biological vulnerability to depression. These hypotheses will be tested in a prospective cohort study and the sample will be composed by 3000 participants, starting from pregnancy, when biological and psychosocial variables will be assessed. Within the first 30 to 60 days after childbirth, these women will be evaluated to verify the occurrence of PPD. IThe results of this study will contribute to a better understanding of the pathogenesis of the DPP, as well as for a more effective and earlier diagnosis and treatment of PPD, avoiding the negative impact of this condition in both mother and child. (AU)