Validation of the Indonesian Version of the Inventory of Statements About Self-Injury (ISAS) Questionnaire

Objective: This current study aimed to validate the Indonesian version of the Inventory of Statements About Self-Injury (ISAS) questionnaire, which provides a better understanding of Non-Suicidal Self-Injury (NSSI) disorders. Method : The study used a cross-sectional design and involved 314 adolescents and young adults in high school or university. A stratified sampling method was used. All participants filled out the ISAS questionnaire. Data were analyzed for content validity, construct validity, item discrimination value, and internal consistency (Croncbach's α). The translation process was carried out using forward and back-translation methods. Results: The ISAS questionnaire consists of section I, the behavioral scale, and section II, the functional scale. For content validity, Aiken's V coefficient obtained for both scale sections I and II is in the range of 0.917 - 1. This result shows that all items on the scale have very good validity. Confirmatory Factor Analyses were carried out using Lisrel 8.80 software on section II, resulting in several goodness of fit values that were not good enough (χ² = 457.68; P < 0.000; df = 64; χ² / df = 7.151, RMSEA = 0.130) and several other values that are quite acceptable (CFI = 0.95; SRMS = 0.057; NFI = 0.95; GFI = 0.83). The factor loading from section II ranges from 0.43 - 0.91. The item discrimination value using the corrected item-total correlation of section I is in the range of 0.031 - 0.837 and section II ranges from 0.290 - 0.854. The reliability analysis values in section I and II of the ISAS are α = 0.527 and α = 0.966, respectively. Conclusion: This is the first study to have validated the Indonesian version of the ISAS questionnaire. The Indonesian version of the ISAS questionnaire is considered a valid and reliable instrument to assess NSSI disorders.