Intervention research in psychosis: issues related to the assessment of quality of life.

Quality of life has emerged as the ideal of modern medicine viewed from a biopsychosocial perspective. The concept has been increasingly used as an important attribute in patient care and clinical studies as well as the basis in many health economic evaluations. Although the concept has been extensively applied in a number of other medical fields such as oncology, cardiovascular, and arthritis, it is only recently that quality of life has received serious attention in the study of severe psychiatric disorders. For the concept to be meaningfully applied in the study of these disorders, several basic and methodological issues have to be adequately resolved. Five such issues are identified: definition of quality of life, the subjective/objective dichotomy, significant determinants of quality of life, how quality of life is measured, and the role of quality of life in clinical management and health economics. Unless these issues are adequately clarified and resolved, the recent heightened interest in the concept of quality of life may fade away, and that would be a missed opportunity in the mental health field.