A systematic review of social functioning outcome measures in schizophrenia with a focus on suitability for intervention research

Social functioning is an important part of recovery and a key treatment target in clinical research in schizophrenia. Evaluating and comparing interventions is challenged by the choice of many measures which focus on different aspects of functioning, with little to guide selection. This results in difficulties comparing outcomes of treatment where studies have used different measures. To improve the measurement of social functioning in intervention research, we aimed to provide practical information on suitability of measures. We conducted a systematic review of measures developed or psychometrically evaluated since 2007, and assessed and discussed the structure, content, quality, and the use of the measures in intervention research. Thirty-two measures of social functioning and 22 validation papers were identified. Measures included structured questionnaires, semistructured interviews, and assessment of performance on specific tasks. The content of measures was organised into eight categories, which are in order of frequency with which they were covered by measures: activities of daily living, productive activity, relationships, leisure activities, cognition, anti-social behaviour, psychosis symptoms and self-esteem and empowerment. In terms of quality, most measures were rated as moderate, with the Personal and Social Performance Scale gaining the highest rating. However, there was little data on responsiveness of measures, or how they compare to objective or 'real-world' indicators of functioning. The Social Functioning Scale and Personal and Social Performance Scale have been most frequently used in intervention studies to date. Future research should aim to provide further data on psychometric properties relevant to intervention research.