In our initial study, 38 mothers with severe postnatal depression (PND) were compared to 46 non-depressed controls over time. Depressed mothers at three months postpartum were found to be less responsive in face-to-face interaction with their infants whom they rated as less reinforcing, less acceptable, less adaptable, more moody and more demanding. PND mothers rated themselves as less competent, less emotionally attached to their child and less healthy. Social and relationship difficulties with their spouse were evident. These differences persisted over a twelve month period, even though the level of depression decreased. In a follow-up study 24 months later, women who had suffered from postnatal depression remained differentiated from control women in terms of their mood, marital relationship and perception of their children. They also rated their children as significantly more symptomatic on behavioural checklists.

In our current study, 60 women have been offered early intervention for their depression at around three months postpartum. Preliminary findings suggest a limited improvement in parent-infant relationships resulting from programs which target depressed mood only, without targeting the mother-infant interaction, despite significant amelioration of depressive states. The relationship between maternal depression and parent-infant attachment is discussed in the context of a proposed model.