An objective method for the assessment of psychosocial problems in adolescents with epilepsy. Psychosocial problems in adolescents with epilepsy have been of concern for many years, but have been difficult to assess. This article presents the multicenter development of the Adolescent Psychosocial Seizure Inventory (APSI), an empirically based self-report test patterned after the Washington Psychosocial Seizure Inventory, which is used to evaluate psychosocial problems in adults. After pilot work, 120 adolescents with epilepsy from five centers in North America took the APSI and were interviewed by professionals with respect to adequacy of adjustment in eight psychosocial areas. At least one parent or guardian was also interviewed. Interrater reliability of professional ratings in each area was established. Using an item-by-item, empirically based technique, eight psychosocial scales were developed as well as three validity scales. Reliability of the scales was established by both internal consistency and test-retest procedures. Results for each adolescent are presented in profile form. These results give a visual display of the types and extent of problems that likely would be identified in a detailed professional assessment. It is anticipated that the APSI will be of value in a variety of treatment and research contexts. 