Reliability and validity of the multidimensional scale of perceived social support in Chinese mainland patients with methadone maintenance treatment

Abstract Introduction The multidimensional scale of perceived social support (MSPSS) is a valid tool for assessing perceived support from family, friends and significant others. However, evidence about reliability and validity of the MSPSS in Chinese mainland patients with methadone maintenance treatment (MMT) is lacking. Methods The patients (n = 1212) being admitted to the first two largest MMT clinics in Xi’an were recruited in the study. Reliability was estimated with Cronbach's α and intra-class correlation (ICC). Convergent and discriminant validity was assessed using item-subscale correlation. Factorial validity was examined using exploratory and confirmatory factor analysis. The patients answered the questions of MSPSS at baseline and re-test after 6 months, respectively. Results Cronbach's α of the overall MSPSS was 0.92 (subscales range: 0.84–0.89). ICC of the overall MSPSS was 0.65 (subscales range: 0.57–0.64). Better convergent validity ( r  ≥ 0.40) was demonstrated by the satisfactory hypothesized item-subscale correlation. All of the hypothesized item-subscale correlations were higher than the correlations between the hypothesized items and other subscales, indicating better discriminant validity. Two factors were extracted from the 12 items, with factor 1 mainly covering friends and significant others subscales (explained 55.56% variance) and factor 2 mainly covering family subscale (explained 11.77% variance). In comparison with the proposed three-subscale model, the two-factor observed model did not fit well in this sample according to model fit indices. Conclusions The MSPSS has acceptable reliability and convergent/discriminant validity in Chinese mainland MMT patients. The proposed three-factor model of MSPSS is much better fit than the two-factor observed model in this study. Findings of the study will provide evidence of psychometric properties of the MSPSS in MMT patient population and expand the use of the MSPSS in clinical MMT context.