Validation of the Polish version of the Neurological Disorders Depression Inventory for Epilepsy (P-NDDI-E)

Summary Introduction. Depressive symptoms are very frequent in the population of patients with epilepsy. Comorbidity between depression and epilepsy is estimated in the range of 9–62%. There are no epidemiological studies in Poland thus far in that area and there is no translated and validated screening tool for depression dedicated for persons with epilepsy (PWEs). In this study we intended to validate the Polish version of the Neurological Disorders Depression Inventory for Epilepsy (NDDI-E), which is a short and accurate scale used in many countries for assessment of depressive symptoms in PWEs. Aim. The purpose of the study was to validate the Polish version of NDDI-E scale in the sample of PWEs. Material and methods. The consecutive 257 patients with epilepsy (PWEs) who met inclusion and exclusion criteria, were recruited by neurologists-epileptologists during their routine outpatient visits in the period from November 2016 to February 2017. The respondents completed the Polish translated version of NDDI-E scale and were assessed with the MINI-International Neuropsychiatric Interview (MINI, depression module). Results. After excluding assessments with missing data, we analyzed data of 253 subjects. Sixty-four patients (25.1%) had current major depressive disorder (MDD) according to the MINI criteria. The Cronbach’s coefficient for the NDDI-E was 0.822. Receiver operating characteristic analyses showed an area under the curve of 0.882 (p < 0.001; asymptotic 95% confidence intervals ranged from 0.832 to 0.932). The cut-off point of 9 corresponded to sensitivity of 0.766 and specificity of 0.858. Conclusion. The Polish version of NDDI-E scale after validation with a cut-off 9 points may be a useful tool for diagnosing depression in a Polish population of PWEs.