French Validation of the International Adjustment Disorder Questionnaire (IADQ) and Exploration of Its Relationship With Transdiagnostic Skills

Abstract: Adjustment disorder (AjD) is a widespread disorder that has remained poorly defined for decades. Recently, the ICD-11 refined the diagnostic concept, and researchers developed the International Adjustment Disorder Questionnaire (IADQ) to assess such conceptualization. The aim of the study was to validate the French version of this questionnaire. A total of 678 participants were recruited. They completed multiple questionnaires: the IADQ, the Adjustment Disorder New Module (ADNM), the Hospital Anxiety Depression Scale (HADS), and the Transdiagnostic Skills Scale (T2S). We assessed the factorial structure of the IADQ using CFA, its internal consistency using McDonald’s ω, and its concurrent validity using Pearson correlations. We found a good factor structure. We also found good concurrent validity and internal consistency. Transdiagnostic skills, such as emotion regulation, were significantly and negatively related to the IADQ scores. The results suggest that the French IADQ provides a reliable and valid assessment of ICD-11 AjD. Interventions that foster transdiagnostic skills may be promising components of treatment protocols for AjD.