The objective of this grant is to continue our longitudinal study of infants and mothers with either high, mid-range, or extremely low levels of depression on maternal and infant outcomes; b) longitudinal observations of naturally occurring maternal and infant interactive behavior are made in the home setting during the first year post partum; c) data on maternal and paternal depressive symptoms, psychiatric co-morbidities, and affective status are collected at each visit; and d) a separate group of mothers with extremely low levels of depressive symptoms is identified and followed. The primary hypotheses to be evaluated are that a) the behavioral and affective styles of mothers with either high or extremely low levels of depressive symptoms will differ from those of mothers with mid-range symptoms; b) patterns of infant behavior and affect will be related to maternal symptom levels; and c) the severity and chronicity of maternal symptoms will have negative effects on mother-infant interaction and infant outcomes. Our hypotheses are guided by the Mutual Regulation Model, which posits that infant development is dependent on the ongoing ability of the infant- caregiver dyad to regulate the infant~s affective states and to foster the infant~s ability to master the major developmental tasks of infancy. The naturally occurring behavior of mothers and infants is videotaped at home when infants are 3,6, and 12 months old. Additionally, infants and mothers are videotaped in the laboratory at 12 months during Ainsworth~s Strange Situation and infant-stranger play. Mothers~ diagnostic history is also obtained. At each age, mothers and fathers complete questionnaires regarding their current depressive symptoms, other psychiatric symptoms, and affective status. Infant and maternal behavior and affect are scored from the videotapes by masked, reliable coders using detailed coding systems. Multivariate techniques will be used to evaluate the hypotheses. Preliminary work and progress on this project has been substantial, and initial results support the hypotheses. This study will markedly increase our understanding of the effects of maternal depressive symptomatology and associated factors on mother-infant interaction and infant socio-emotional development during the first year.