Testing psychometric properties of the Thai Social Dysfunction Rating Scale (TSDRS) in schizophrenic and methamphetamine abuse patients

Abstract

Background: Measuring patient outcomes and early detection is important to prevent severe social dysfunction in schizophrenic and methamphetamine abuse patients. Psychometric properties testing of the Thai Social Dysfunction Rating Scale (TSDRS) has not yet been applied.

Method: Factor analysis was carried out on data collected from 313 schizophrenic and methamphetamine abuse patients who met the inclusion criteria, and who were recruited using multi-stage sampling from eight setting of psychiatric and substance disorder service care in Thailand during April to May, 2015. The method of extraction was principal components analysis. Parallel Analysis with Monte Carlo Simulations (PAMC) was used to determine the factor’s number to retain in a factor analysis.

Results: A 14-item TSDRS was applied to 313 participants. Communalities in each factor ranged from .54 to .79 that were retained. The Kaiser-Meyer-Olkin measure of sampling adequacy = .93 and Bartlett’s test was X² = 2867, df = 91, p<0.001. Cronbach’s alpha and test retest reliability was .93, .96 respectively. Confirmatory factor analysis indicated that all items have fit with the empirical data (X² = 26.544; df = 32; X²/df = .83; CFI = 1.00; NFI = 0.99; GFI = .96; PGFI =.40; IFI = 1.02; RMR = .15; and RMSEA = .00). Factor structures showed that items were accepted. Factor loading ranged from .57 to .86 were practically significant. Two factors, explaining 66.2% of the total variance, were identified. Factors 1 explained 56.3% and factor 2 explained 9.9% of the variance.

Conclusion: The TSDRS demonstrated acceptable psychometric properties and practical measurements for health care providers to assess social dysfunction in schizophrenic and methamphetamine abuse patients.