This is the twenty-seventh report in a monograph series authorized by the Board of Trustees of the American Psychiatric Association to give wider dissemination to the findings of the Association's many commissions, committees, and task forces that are called upon from time to time to evaluate the state of the art in a problem area of current concern to the profession, to related disciplines, and to the public. Manifestly, the findings, opinions, and conclusions of the Task Force Reports do not necessarily represent the views of the officers, trustees, or all members of the Association. Each report, however, does represent the thoughtful judgment and consensus of the task force of experts who formulated it. These reports are considered a substantive contribution to the ongoing analysis and evaluation of problems, issues, and practices in a given area of concern.