Reciprocal influences and adaptation over time for mentally retarded children and their families will be evaluated in a longitudinal (5 years) follow-up of a representative sample of 150 families of school-age children with mild and moderate mental retardation. The study will focus on family interactions as proximal and potentially modifiable predictors of adjustment for all family members, and thus will suggest avenues for interventions to prevent deterioration in social and cognitive adjustment for the child, and to avoid distress and disruption for the other family members. The families were originally evaluated when the children were 6-18 years old, and were seen a second time 18-24 months later. For this third assessment, the family members will again complete structured and unstructured interaction sessions in their homes, which will be observationally coded to assess behavior management practices, family problem solving, supportiveness, and aversiveness among the family members. The quality of the parents' marital relationship, family stress, coping resources, and the psychosocial adjustment of the mentally retarded child also will be assessed at Time 3. Changes across time and predictive relationships among the measures will be examined to test the hypothesis that characteristics of the child, marital quality, family stress and coping resources each influence family interactions with a mentally retarded child, which in turn affect the child's psychosocial adjustment and cognitive and social development. This third assessment also will explicate cognitive factors related to distorted perceptions, cognitive biases, expectations, attributional sets, goals, values, and beliefs by the parents which can either foster positive adaptation or lead to conflict, hostility, and aversive interactions with the child. Additionally, at Time 3 the families of mentally retarded children will be contrasted with two pertinent comparison groups, families with children with a chronic illness or physical handicap (n=60), and families of behavior disordered children (n=60). These comparisons will determine the characteristics of family interactions and adaptation that are uniquely important to families raising a mentally retarded child, the influence of physical disabilities on child and family adjustment, and how family adaptation is linked to behavior problems in handicapped and nonhandicapped children.