S1 Dataset -

Objective
The Difficulties in Emotion Regulation Scale-18 (DERS-18) is an instrument used to measure deficits in emotion regulation. However, the instrument has not been adapted to Malaysians and has never been validated in the Malay language. This study aimed to examine the psychometric properties of the Malay version of DERS-18.
Method
The DERS-18 underwent forward-backward translation and assessment of face and content validity. Both Malay version of the DERS-18 and DASS-21 were completed by 701 adolescents (44.4% boys) aged 13 and 14 years old. To assess its dependability, a floor and ceiling effect evaluation and Cronbach’s analysis were both performed. A series of confirmatory factor analyses (CFA), bivariate correlation, and regression were performed to evaluate the construct and criterion validity, respectively.
Results
The Malay version of DERS-18, after excluding “Awareness”, indicated excellent reliability (Cronbach’s α = 0.93), and acceptable internal consistency for each subscale (range of α from 0.63 to 0.82). Floor or ceiling effects were observed at item level and subscale level, but not at total level. CFA results revealed that the Malay version of the DERS-18 bifactor model (excluding “Awareness”) portrayed the best construct validity (χ2/df = 2.673, RMSEA = 0.049, CFI = 0.977, TLI = 0.968) compared to a single factor, a correlated factor, and a higher-order factor model. The DERS-18 subscales (except “Awareness”) and DERS-18 total scores were significantly correlated with stress, anxiety, and depression in a positive direction (r ranged from 0.62 to 0.64, p < 0.01). The general factor of the DERS-18 and its specific factors (“Clarity”, “Goals”, and “Non-Acceptance”) significantly predicted the symptoms of stress, anxiety, and depression (R2 ranged from 0.44 to 0.46, p < 0.001).
Conclusion
The Malay version of the DERS-18, excluding “Awareness”, possessed good reliability, construct validity, and criterion validity to assess emotion dysregulation among Malaysian adolescents.