Measuring quality of life in patients with schizophrenia: an update.

In 1997, we published a review in PharmacoEconomics about quality of life (QOL) measurement in patients with schizophrenia. The objective of this article is to provide an update, as well as to revisit the development of the construct of QOL and its measurement as applied to schizophrenia. Since our previous article, there has been significant growth in the number of publications about QOL in schizophrenia. Unfortunately, alongside this significant increase in research interest, a number of concerns have also risen about the limitations and lack of impact the concept of QOL has on clinical care and health-policy decision making. A number of concerns previously outlined (such as lack of consensus on a uniform definition of QOL) continue to be an issue. However, we believe that a uniform definition may not be possible, and instead, it may be preferable to have several definitions, which may enrich the concept and broaden its usefulness. Some of the scales we reviewed in 1997 continue to be in use, while others are now rarely or never used. New scales with better psychometrics have been introduced, but most are without theoretical or conceptual foundation. On the other hand, the field of scaling in general has been changing over the past few years and is moving towards a new approach for scale development, based on item response theory, item banks and computer adaptive testing. Unfortunately, this has not extended to QOL in schizophrenia. There continues to be a dearth of theoretical and conceptual models for QOL in schizophrenia, which seems to create the perception that the construct lacks a good theoretical and scientific foundation. One of the major gaps identified in this review is the recognized lack of impact of QOL measurements on clinical management or policy decision making. The majority of publications continue to focus on measurement rather than what to do with the data. The lack of strategies to integrate QOL data in clinical care, as well as the failure to contribute to policy decisions, particularly in cost analysis or resource allocations, has created the perception that the construct of QOL in schizophrenia is not that useful. It is evident that, for QOL in schizophrenia to regain its promise, researchers must take the ultimate next step beyond measurement: to develop credible strategies for integrating QOL data in clinical practice. Additionally, more focused research is needed to demonstrate the role of QOL, not only as an outcome in itself but also as a contributor to other outcomes, such as adherence to medications, more satisfaction, less resource utilization and so on. Since self-appraisal of QOL does not happen in a vacuum but relates to the total human experience in all its biological, psychosocial and environmental aspects, particular attention must also be focused on important neurobiological dimensions such as affect and cognition. Both are significantly affected by the illness itself and its treatment.