Psychosocial interventions in chronic medical illness. An overview of outcome research.

Previous studies have shown that psychopathology is common in the medically ill, affects the course of medical illness, and is associated with increased health care costs. Recent controlled trials have demonstrated that psychosocial interventions in the medically ill can improve both psychosocial and medical outcomes. Although an important aim of current research is to assess the cost effectiveness of such interventions, the meaning and significance of "cost effectiveness," "cost benefit," and "cost offset" are frequently misunderstood. An overview of outcome research will be used to illuminate the promise and the limitations of such studies, with special attention to bias in research design.