Validation of the Thai version of the Neurological Disorders Depression Inventory for Epilepsy (NDDI-E): Screening for major depressive disorder in patients with epilepsy

Abstract

Introduction Depression has been recognized as a common comorbidity in patient with epilepsy and is associated with low quality of life. Regular screening for depression may aid in early detection and enhance quality of life. Objectives To validate the Thai version of the Neurological Disorders Depression Inventory for Epilepsy (NDDI-E). Methods The English version of NDDI-E was translated into Thai. Patients with epilepsy were enrolled at the outpatient neurology clinic from May 2019 to September 2019. Demographic data and clinical characteristics were collected. Participants underwent a psychiatric structured interview using the Mini-International Neuropsychiatric Interview (M.I.N.I.) as a gold standard for the diagnosis of major depressive disorder. Then, participants completed the NDDI-E. The internal consistency was measured by Cronbach’s alpha coefficient. The validity of the Thai version of the NDDI-E was assessed using the receiver operating characteristic (ROC) curve analysis. Youden’s index was used to determine the optimal cut-off score of the Thai version of the NDDI-E. Results A total of 115 patients with epilepsy completed the evaluation. Twenty-three patients (20%) had major depressive disorder according to M.I.N.I. criteria. The Cronbach’s alpha coefficient of the Thai version of the NDDI-E was 0.826. The area under the ROC curve was 0.995. A cut-off score greater than 17 provided a sensitivity of 95.65%, a specificity of 97.83%, a positive predictive value of 91.67% ,and a negative predictive value of 98.90%.Table 1: Demographic and clinical characteristics of the study population. Non-depressed (N = 92) Major depression(N = 23) P-value Age in years, median (IQR) 31 (22) 28 (30) 0.637 Female, N (%) 50 (54.3) 15 (65.2) 0.347 Comorbid medical illnesses, N (%) 0.009 Present 40 (43.5) 17 (73.9) Absent 52 (56.5) 6 (26.1) Years since onset of seizures, mean (SD) 19.4 (11.9) 16.4 (14.1) 0.297 Seizure free for the last 6 months, N (%) 55 (59.8) 10 (43.5) 0.158 NDDI-E score, median (IQR) 12 (5) 19 (4) <0.001 Table 2: Corrected item-total correlation and Cronbach’s alpha if an item is deleted from the NDDI-E. Corrected item-total correlation Cronbach’s alpha if item deleted 1. Everything is a struggle 0.554 0.807 2. Nothing I do is right 0.590 0.800 3. Feel guilty 0.573 0.803 4. I’d be better off dead 0.643 0.788 5. Frustrated 0.660 0.784 6. Difficulty finding pleasure 0.548 0.808 Conclusions The Thai version of the NDDI-E is a valid screening tool for major depressive disorder in patients with epilepsy. Disclosure of Interest None Declared