Beyond negative emotion dysregulation: factor structure, measurement invariance, and incremental validity evidence for the Persian difficulties in emotion regulation scale–expanded in Iranian community and clinical samples

The Difficulties in Emotion Regulation Scale–Expanded (DERS-X) assesses difficulties in regulating negative and positive emotions. However, cross-cultural evidence for its factor structure and relevance to affective symptoms remains limited. This psychometric validation study translated, adapted, and evaluated the Persian DERS-X in Iranian community and clinical samples. Study 1 included 562 community participants (mean age = 26.72, standard deviation [SD] = 10.09), and Study 2 included 171 clinical participants with diagnoses based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) (mean age = 30.57, SD = 10.60). Analyses examined factor structure, reliability, group comparability, and external associations. We evaluated the added role of positive-emotion difficulties after negative-emotion difficulties were considered, and the added value of the Persian DERS-X beyond related measures. Across both samples, the 11 correlated first-order subscale model showed the best fit and was retained as the preferred structure. Broader composite scores were treated as observed summaries. Internal consistency was adequate to strong, and broader scores showed stronger temporal stability than subscales. Latent factor correlations indicated that DERS-X dimensions were generally distinguishable, although some related subscales overlapped in the clinical sample. Scalar invariance was supported across gender, age, and clinical status. Scores showed expected associations with emotional intelligence, experiential avoidance, and related emotion-regulation measures. Positive-emotion difficulties added information for distress outcomes in the community sample and depressive symptoms in the clinical sample. The scale also added information beyond related measures. Findings extend cross-cultural evidence for DERS-X score interpretations and support the Persian version as an 11-dimensional measure for research and clinically informed assessment of negative- and positive-emotion regulation difficulties.