To examine the adjustment of nondisabled siblings of handicapped children.

In a 3-year longitudinal study, 46 siblings of children with pervasive developmental disorder (PDD), 45 siblings of children with Down syndrome, and 46 siblings of developmentally normal children (serving as controls) were examined at time 1 using the sibling, primary caretaker, and teacher as informants. Both direct and indirect variables related to sibling adjustment were considered.

Significantly more difficulties were found in the siblings of children with PDD compared with the other two groups. Different correlates of adjustment were present in the siblings of the disabled compared with nondisabled children, and mediating factors differed in parent and teacher reports of internalizing difficulties in siblings of children with PDD. Marital satisfaction, lack of parental depression, a cohesive family, and a warm, nonconflictual sibling relationship were protective for normal control and Down syndrome siblings but not for PDD siblings.

Findings underline the risks for the siblings of children with PDD and suggest the importance of a transactional mechanism rather than identification of single risk or protective factors in predicting sibling adjustment. Subsequent data analysis in this longitudinal study will assist in defining these mechanisms and allow for improved intervention strategies.