Rationale and Hypotheses of the Current Research: the investigators speculate that mothers suffering from PPD exhibit high levels of depression and low levels of OXT, hence experiencing the interaction with their child as less rewarding, which in turn promote further depressive symptoms and interfere with child development. While dyadic psychotherapy has been studied in this context, it is unknown which depressed women will respond to this type of therapy, and whether such a response is mediated by the pro-bonding effect of oxytocin.