The role of self-esteem instability in the development of postnatal depression: A prospective study testing a diathesis-stress account

• First study to investigate self-esteem instability and postnatal depression.
• Self-esteem instability predicts postnatal depressive symptomatology.
• Level of self-esteem does not predict postnatal depressive symptomatology.
• SE instability relates with changes in day-to-day levels of depressed mood state.

Background and objectivesUnderstanding vulnerability factors involved in the development of postnatal depression has important implications for theory and practice. In this prospective study, we investigated whether self-esteem instability during pregnancy would better predict postnatal depressive symptomatology than level of self-esteem. In addition, going beyond former studies, we tested the possible origin of this instability, examining whether day-to-day fluctuations in self-esteem could be explained by fluctuations in mood state, and whether this day-to-day self-esteem reactivity would predict postnatal depressive symptoms.Methods114 healthy never-depressed women were tested during the late second or third trimester of their gestation (Time 1) and at 12 weeks after delivery (Time 2). Day-to-day levels of self-esteem and depressed mood state were assessed at Time 1. At Time 2, postnatal depressive symptoms were assessed.ResultsThe results show that, after controlling for initial depressive symptomatology, age and socio-economic status, postnatal depressive symptomatology at 12 weeks after childbirth could be predicted by self-esteem instability and not level of self-esteem. In addition, multi-level analyses demonstrated that these changes in day-to-day levels of self-esteem are associated with changes in day-to-day levels of depressed mood state and that those subjects with greater prenatal self-esteem reactivity upon depressed mood report higher levels of depressive symptoms post-partum.LimitationsWe used paper and pencil day-to-day measures of state self-esteem, which can be subject to bias.ConclusionThese results provide evidence for a diathesis-stress account of postnatal depression, highlighting the importance of a multi-dimensional view of self-esteem and the predictive role of self-esteem instability.