Psychometric Evaluation of Indonesian Version of the Somatic Symptom Scale-8 (ISSS-8)

Somatic symptom disorders (SSDs) refer to a group of patients experiencing distressing physical symptoms accompanied by excessive thoughts, feelings, or behaviors related to these symptoms. SSDs are associated with various medical and psychiatric conditions, leading to significant healthcare costs. Therefore, early identification and intervention for SSD are crucial. The Somatic Symptom Scale-8 (SSS-8) is an efficient and valuable self-report instrument for assessing the burden of somatic symptoms. Therefore, this study has two main objectives; Firstly, translating the SSS-8 to suit the Indonesian population by creating the Indonesian version, known as ISSS-8, and secondly, comprehensively assessing the psychometric characteristics of the ISSS-8.

The SSS-8 items was translated into Bahasa Indonesian using WHO translation method and produced ISSS-8. The second phase involved evaluating the scale's psychometric properties, including construct validity and reliability. Confirmatory factor analysis (CFA) and Cronbach alpha testing was performed.

The Cronbach's alpha outcomes affirmed the reliability of ISSS-8 with score of α=0.627. Additionally, CFA confirmed the singular-factor structure of SSS-8 with fit model (χ²/df=0.126, CFI=0.957, GFI=0.881, RMSEA=0.053, and SRMR=0.054).

The ISSS-8 proved to be a valid and reliable instrument for evaluating somatic symptoms in the adult population. It exhibited acceptable validity and reliability, consistent with prior research conducted in diverse cultural settings. These results affirm the effectiveness of ISSS-8 as a valuable screening tool for identifying somatic symptoms within the Indonesian-speaking population.