Psychometric Properties of the Internalized Stigma of Mental Illness (ISMI) Scale in Indonesia

Objective: The Internalized Stigma of Mental Illness (ISMI) scale is widely used to examine internalized stigma among people with mental illness. However, an Indonesian version does not yet exist. We developed an Indonesian translation of the ISMI scale and assessed its psychometric properties. Method: We included 280 inpatients with mental illness diagnoses in 2 hospitals and a rehabilitation center. We followed the guidelines proposed by Sousa and Rojjanasrirat (2011) to translate the questionnaire. The reliability was evaluated by measuring the internal consistency (Cronbach's alpha) and test-retest reliability. Test validity was measured through exploratory factor analysis (EFA) to examine the structure of the scale and confirmatory factor analysis (CFA) to determine the model fits. Results: The EFA yielded 5 factors with Cronbach's alpha coefficients of .96 for the total scale and .95, .95, .93, .94, and .82 for the 5 subscales. The test-retest reliability indicated excellent results, demonstrated by the interclass correlation coefficient ranging between .76 and .92 for all ISMI scale items. The Kaiser- Meyer-Olkin test statistic was 0.95, and Bartlett's test of sphericity value was significant. Conclusions and Implications for Practice: The CFA indicated that the ISMI scale has an acceptable model fit. The Indonesian version of the ISMI scale demonstrated good psychometric properties for measuring internalized stigma of psychiatric patients in Indonesia.