Translation and validation of the Turkish forms of the International Depression Questionnaire (IDQ) and the International Anxiety Questionnaire (IAQ)

Background: The 11th version of the International Classification of Diseases (ICD-11) included revised formulations of single episode depressive disorder (DD) and generalized anxiety disorder (GAD). Consequently, the International Depression Questionnaire (IDQ) and International Anxiety Questionnaire (IAQ) have been developed as self-report measures which directly align with the ICD-11 description of DD and GAD, respectively. Objective: The current study sought to (1) test the factorial validity of the Turkish translations of the IDQ and IAQ, (2) evaluate their internal reliability, (3) determine how meeting diagnostic requirements for ICD-11 DD and ICD-11 GAD vary across different demographic variables, and (4) determine the convergent validity of the Turkish translations of the IDQ and IAQ. Methods: Participants were a community sample of 1455 Turkish adults and largely comprised of university students. This study used confirmatory factor analysis (CFA) to test the latent structure of both scales. Prevalence rates of ICD-11 GAD and DD were also estimated, and differences in prevalence rates according to gender and relationship status were examined. Results: The CFA results indicated that both scales were unidimensional. Both scales demonstrated high levels of internal consistency. The prevalence of ICD-11 DD and GAD was 26.6 % and 28.5 %, respectively. Rates of probable ICD-11 DD and GAD were highest for females and single participants. Convergent validity was indicated by strong associations with external measures of depression and anxiety. Conclusion: Findings from this study provide support for the validity and reliability of the Turkish versions of the IDQ and IAQ in a large community sample.