Randomized controlled trial of the Circle of Security-Intensive intervention for mothers with postpartum depression: maternal unresolved attachment moderates changes in sensitivity

Postpartum depression is related to inadequately sensitive caregiving, putting infants at risk for insecure attachment. Therefore, promoting sensitive maternal caregiving and secure child attachment is particularly important in postpartum depressed mothers and their infants. In this randomized-controlled-trial, we evaluated the efficacy of the Circle of Security-Intensive (COS-I)-intervention in supporting maternal sensitivity and mother-infant-attachment compared to treatment-as-usual (TAU) with unresolved-maternal attachment as a moderator of treatment effect. Eligible mothers with infants (N=72) 4-9 months-old were randomly assigned to treatment (n=36 dyads). Infant attachment was rated at follow-up (child age 16-18 months) (Strange-Situation-procedure). Maternal sensitivity was measured at baseline and follow-up (Mini-Maternal-Behavior-Q-sort). Maternal-unresolved-attachment was assessed at baseline (Adult-Attachment-Interview). We found no significant differences between treatments in infant attachment nor changes in mothers' sensitivity. However, in COS-I, unresolved-mothers exhibited significantly more change in sensitivity than non-unresolved-mothers, whereas in TAU, the opposite was true. These findings may help to optimize clinical use of COS-I.