The objective of this study is to examine the impact of a home-based peer support intervention for mothers affected by postpartum depression (PPD) and for their infants.

This controlled study will help establish the link between support for maternal caregiving, maternal-infant interaction, infant neuroendocrinology and infant cognitive and social development. The primary hypothesis predicts that home-based peer support will improve maternal-infant interactions. Secondary hypotheses predict that home-based peer support will: improve infants' cognitive development; improve infants' social development; decrease average daily salivary cortisol levels in infants; reduce maternal depressive symptomatology; and improve maternal perceptions of social support.

Inclusion Criteria:

• Eligible mothers will be identified as experiencing symptoms of PPD and scores >12 on the Edinburgh Postnatal Depression Scale.
• Mothers must speak English or French.
• Mothers will not be excluded for taking anti-depressant or anti-psychotic medication, using other interventions for PPD, or reporting a history of mental illness;
• The infant must be full-term, in the care of the mother and between 3 to 6 months of age at initial enrollment.

Exclusion Criteria:

• Infants who have been admitted to the NICU
• Infants will be excluded if medicated with corticosteroids