The Effect of Early Dyadic Psychotherapeutic Intervention for Mothers Suffering From PPD on Oxytocin Level and on Childrens' Emotional and Behavioral Development

Background: Postpartum depression follows approximately 10-15% of deliveries. Maternal functional disability, particularly in the relationship with the infant, a hallmark of PPD, causes impairment in the mother's ability to bond with her infant. Subsequently, this impairment leads to deleterious long-term consequences for infant cognitive, neurological, and social-emotional growth, and is associated with psychiatric disorders in later life. Recently, biological correlates of maternal deprivation and maternal depression on the infant's brain in both animal and human studies have been found . Therefore, the development of effective short-term treatment in such a highly prevalent phenomenon is of a high clinical priority. While pharmacological and psychological treatments are effective in treating PPD, these interventions have failed to show a significant improvement in mother-child interaction quality and infant development.

The Oxytocin System: Oxytocin (OXT) is a nine amino acid neuro-peptide, found exclusively in mammals and is released during labor and lactation. The effects of OXT on the anterior cingulate, OFC and vmPFC, suggesting its effect on 'social brain' areas have been reported in the past , including modulation of maternal behaviors and paternal behaviors including positive affect, social gaze, touch, and vocal synchrony with the infant . Among the central influences of OXT on human social behavior are increased trust , empathy and eye contact . Brain imaging found that maternal attachment activates regions in the brain's reward systems that are rich with oxytocin and vasopressin receptors . Such findings led researchers to speculate that OXT may be involved in linking and maintaining the connection between social recognition systems and feelings of pleasure . According to this speculation, pair bonding is a form of conditioned reward learning, whereby OXT promotes the reward in social encounters, thus enhancing the motivation to engage in such interaction .

Disruptions to the oxytocin system in depression have been repeatedly observed, and woman suffering from PPD have lower plasma OXT concentrations in comparison to the control group . Recent studies investigated the therapeutic potential of OXT in psychopathologies involving impaired social functioning such as autism spectrum disorders where OXT was found to facilitate social information processing and retention of social information, in social anxiety disorder , and schizophrenia where OXT administration resulted in a significant improvement in several social cognition measures and symptom reduction. Furthermore, a recent small treatment study of OXT in women suffering from PPD did not show a positive effect on mood; however, it did show improved mother-child interactions.

Studies suggest a bio-behavioral feedback loop of OXT, parenting, and infant social competence. The mechanisms of cross-generation transmission in the OXT system have been observed in human parents and infants in the first months of the infant's life and showed that parent and child's OXT levels are highly correlated and higher parental OXT was associated with higher infant OXT. Studies in non-human primates have shown long-term consequences on the development of social competence and infant's ultimate parental skills.

Rationale and Hypotheses of the Current Research: We 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.