Bridging Disciplinary Boundaries (January 11 - 14, 2007)

Purpose: Quality of life has been recognized as an important outcome of schizophrenia treatment. One factor that has consistently been shown to negatively influence quality of life is psychiatric symptoms. However, due to significant variation in measurement strategies and definitions of quality of life across existing studies, it has been difficult to identify which symptoms pose the greatest threat to quality of life. Furthermore, the magnitude of the effect of psychiatric symptoms on quality of life has also been difficult to discern, with studies varying widely in their estimates of these relationships. Clarifying the relationship between psychiatric symptoms and quality of life represents an important step in elucidating the influences of quality of life in schizophrenia that could help guide treatment development efforts. The purpose of this research was to conduct a systematic meta-analysis of all existing studies, both published and unpublished, examining the influence of psychiatric symptoms on quality of life in schizophrenia, in order to achieve a clear understanding of the importance of these symptoms to the quality of life of individuals suffering from this illness.

Methods: An extensive literature search of relevant abstract databases, key journals, empirical reports, as well as unpublished reports from prominent quality of life researchers was conducted to locate studies documenting the relationship between psychiatric symptoms and quality of life in schizophrenia. A total of 56 studies (52 published and 4 unpublished) were identified, yielding 79 effect sizes of the relationship between psychiatric symptoms and quality of life. These effect sizes were subjected to meta-analytic procedures to estimate the overall impact of various psychiatric symptoms on quality of life, and explore systematic sources of variation among these effects.

Results: Findings indicate that small to moderate negative relationships exist between various psychiatric symptoms and quality of life in schizophrenia (range of r = -.20 to -.34), with general psychopathology (e.g., anxiety, depression) consistently emerging as the largest symptomatic contributor to poor quality of life. Moderator analyses suggested that positive and negative symptoms had a particularly negative impact on the quality of life of schizophrenia outpatients, all Q_B(1) > 4.94, all p < .05, although anxiety and depressive symptoms influenced the quality of life of inpatients and outpatients equally, Q_B(1) = .01, ns.

Implications: These findings suggest that psychiatric symptoms, particularly general psychopathology, are important, but modest contributors to quality of life in schizophrenia, and that their influence depends in part on particular sample under study. Such findings highlight the need for treatment developers attempting to improve the quality of life of individuals with this disorder to look beyond positive and negative symptoms, and attend to disabling anxiety and depressive symptoms as well. Furthermore, the modest size of the effects of psychiatric symptoms on quality of life underscore the need to examine additional, psychosocial influences of quality of life. With its multidisciplinary, biopsychosocial perspective, social work is in a unique position to contribute to effective treatment development efforts to improve quality of life among individuals with this illness.