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Reproducibility and Minimal Detectable Change of Internalized Stigma of Mental Illness (ISMI) Scale in Patients with Mental Illness

Research output: Contribution to journalArticlepeer-review

Chung-Ying Lin, Chih-Cheng Chang

Original languageEnglish
Pages (from-to)177-184
JournalTaiwanese Journal of Psychiatry
Issue number3
PublishedSep 2016

King's Authors


Objective: Self-stigma which is a critical issue, needs to be cared by the mental health professionals, and the Internalized Stigma of Mental Illness (ISMI) scale is one of the most commonly used instrument measuring self-stigma. But the information of its reproducibility, especially the minimal detectable change (MDC), remains largely unknown. Therefore, the applicability of the ISMI is somewhat limited. In this study, we intended to study the reproducibility of the ISMI in patients with mental illnesses through different lengths of test-retests. Methods: People with mental illness (n = 145) completed the ISMI twice within an interval of 2 weeks to 3 months; 116 of them within 2 months; and 75 within 1 month. The intraclass correlation coeffi cient (ICC) was used to examine the reproducibility, and MDC was further calculated using ICC results. Furthermore, MDC% was computed to understand whether the reproducibility is acceptable (< 30% indicates acceptable). Results: The reproducibility of the ISMI was better in a shorter test-retest interval (3-month interval: ICC = 0.53 to 0.80; 2-month: ICC = 0.55 to 0.82; 1-month: ICC = 0.69 to 0.89). The MDC for the total score of the ISMI was 19.57 (three-month interval), 19.26 (two-month interval), and 14.08 (one-month interval). We also found that the patients had significantly reduced self-stigma in one month (p < 0.05). MDC% revealed that the reproducibility for the total score of the ISMI was nearly acceptable in three-month interval (30.16%) and acceptable in 2- and 1-month intervals (29.44% and 21.74%, p < 0.05). Conclusion: The total score of the ISMI is reliable in monitoring the self-stigma in patients with mental illness within an interval of two months.

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