Psychometric evaluation of the Korean version of the Suicidal Ideation Scale in mentally ill patients living in the community

Objective:The purpose of this study was to translate the Suicidal Ideation Scale (SIS) into Korean (SIS-K) and then evaluate its psychometric properties in mentally ill Korean patients living in the community. Methods:The SIS-K was translated into Korean using a translation and back-translation technique. A sample of 396 patients with mental disorders was recruited from regional mental health centres in Korea. Factorial-construct validity was tested using both exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). The data were randomly split into two subsamples: one used for EFA to identify the underlying structure of the items, and the other used for CFA to test whether the underlying structure was supported by actual data. Convergent validity, known-groups validity and internal-consistency reliability were tested. Results:Exploratory factor analysis extracted nine items clustered into two subscales that accounted for 68.59% of the variance. One item ('I feel there is no solution to my problems other than taking my own life') was deleted. The structure of the two subscales was supported by CFA. The SIS-K score was moderately correlated with depression, and the scale demonstrated convergent validity. The SIS-K scores were significantly higher in patients who had attempted suicide, implying the presence of satisfactory known-groups validity. Cronbach's alpha of the total SIS-K was 0.91. Conclusions:The study has demonstrated the excellent psychometric properties of the SIS-K. The SIS-K is brief and easy to complete, and so it can be applied in both practice and research to patients with mental disorders. This cultural validation of the SIS-K will promote both domestic and international studies of suicidal ideation.