Cross-cultural adaptation and psychometric validation of the Cognitive Distortions Questionnaire for Adolescents (CD-Quest-T) in European Portuguese

Abstract Background Cognitive distortions are maladaptive thought patterns associated with emotional disorders during adolescence. Valid and culturally adapted instruments are needed to support adolescent mental health assessment and promotion in educational, primary care, clinical, and nursing settings. Objective This study aimed to translate, culturally adapt, and validate the European Portuguese version of the Cognitive Distortions Questionnaire for Adolescents (CD-Quest-T) and examine its psychometric properties in a school-based adolescent sample. Methods A total of 851 adolescents aged 14 to 19 years completed the CD-Quest-T, the Generalized Anxiety Disorder-7 (GAD-7), and the Patient Health Questionnaire-9 (PHQ-9). Translation and cultural adaptation followed International Test Commission guidelines. The sample was randomly split for exploratory factor analysis (EFA; n = 425) and confirmatory factor analysis (CFA; n = 426). Internal consistency and convergent validity were examined. Results EFA supported a unidimensional structure, with the first factor explaining 54.58% of the variance. CFA indicated adequate model fit: χ²(20) = 31.69, p = .047, CFI = 0.931, TLI = 0.904, RMSEA = 0.037, and SRMR = 0.024. CFA standardized factor loadings ranged from 0.420 to 0.752. Internal consistency was good, with Cronbach's α = 0.87. Positive correlations with anxiety (r = 0.58, p < .001) and depression (r = 0.54, p < .001) supported convergent validity. Conclusions The European Portuguese CD-Quest-T demonstrated adequate psychometric properties and may support adolescent mental health screening, psychoeducation, referral, and nursing practice.