Examining risk factors and mechanisms that contribute to vulnerability to psychopathology allows for exploration of underlying processes. Risk research distinguishes between risk factors, which increase the statistical likelihood of a disorder, and vulnerability factors, which are more proximal to the child and represent causal mechanisms in the chain of events leading to the onset of psychopathology. Risk factors for depression include both biological and environmental factors. Parent-proband and child-proband family studies demonstrate clustering of depression in families. Thus, parental depression represents a risk factor for depression in youth. Vulnerability factors for child depression have also been examined. Social information-processing models specify cognitive factors -- including a pessimistic explanatory style and negative cognitive errors -- as potential vulnerabilities; whereas, interpersonal/attachment models specify dysfunctional internal working models as potential vuinerabilities. Parental depression may increase depression vulnerability through a number of potential mechanisms, both biological and psychosocial. Psychosocial risk mechanisms include negative life events and family stress. ? ? Family expressed emotion (EE), a measure of family emotional climate, strongly predicts outcome among adults with mood disorders. More recent work indicates that depressed children may be particularly likely to live with a high EE parent; high EE predicts more negative one-year outcome in children following hospitalization for depression; and parental depression increases the likelihood that parents will be high EE. Thus, parental EE may represent one mechanism by which parental depression increases depression vulnerability; however, its' relationship to depression onset in youth has not yet been established. Only recently have researchers begun to explore the links between risk and vulnerability in child depression. Utilizing a longitudinal design in a sample of pre-adolescents with and without a depressed mother, we propose to examine the links between a known risk factor (parental depression), a potentially important psychosocial mechanism (EE), the development of cognitive-interpersonal vulnerability, and the manifestation of both depressive symptoms and disorders during a critical period in the development of coping and self-concept. ? ?