[Preparation for the Hungarian adaptation of the Neurological Disorders Depression Inventory for Epilepsy (NDDI-E)]

Introduction: Epilepsy is a chronic neurological disease with a significant burden worldwide, often associated with comorbidities, particularly depression. Depression does not only impair quality of life but also affects the effectiveness of epilepsy treatment. The NDDI-E (Neurological Disorders Depression Inventory for Epilepsy) is a short, targeted questionnaire developed to rapidly identify depression in people with epilepsy. Objective: The aim of our study is to prepare the ground for the validation and adaptation of the NDDI-E questionnaire in Hungarian. Method: 83 epilepsy patients (54 women and 29 men) with a mean age of 47.253 years (SD = 14.613) were included in our study. The NDDI-E questionnaire was compared with the Beck Depression Questionnaire (BDI) and other psychometric instruments (Quality of Life in Epilepsy [QOLIE-31], Patient Health Questionnaire-9 [PHQ-9]). The methodological process included a back-and-forth translation of the questionnaires and expert validation. Results: The internal reliability of the NDDI-E was Cronbach’s α = 0.8, which increased to 0.885 during retest. The results of the confirmatory factor analysis showed that the one-dimensional structure of the NDDI-E matched the data well. The analysis confirmed the presence of a single component, with each item contributing a corresponding factor weight; the lowest factor weight was 0.440 and the highest was 0.762. Total questionnaire scores showed a significant positive correlation with BDI scores (r [81] = 0.574; p<0.001). NDDI-E scores predicted changes in the quality of life (QOLIE-31). Maximum sensitivity and specificity showed optimal predictive value in diagnosing depression. The external validity of the questionnaire was supported by the strong correlation with PHQ-9 and BDI scores. Discussion: The results support the applicability of the NDDI-E in a Hungarian-speaking epilepsy population, and the questionnaire may serve as a reliable tool for the rapid screening of depression. Conclusion: Future studies with a larger number of items are needed to further confirm the validity and reliability of the questionnaire. Orv Hetil. 2025; 166(46): 1810–1817.