Rapid detection of generalized anxiety disorder and major depression in epilepsy: Validation of the GAD-7 as a complementary tool to the NDDI-E in a French sample

Abstract Objective Generalized anxiety disorder (GAD) in people with epilepsy (PWE) is underdiagnosed and undertreated. The GAD-7 is a screening questionnaire to detect GAD. However, the usefulness of the GAD-7 as a screening tool in PWE remains to be validated. Thus, we aimed to: (1) validate the GAD-7 in French PWE and (2) assess its complementarity with regard to the previously validated screening tool for depression, the Neurological Disorders Depression Inventory for Epilepsy (NDDI-E). Methods This study was performed under the auspices of the ILAE Commission on Neuropsychiatry. People with epilepsy > 18 years of age were recruited from the specialist epilepsy unit in Marseille, France. The Mini-International Neuropsychiatric Interview (MINI) was performed as gold standard, and the Penn State Worry Questionnaire (PSWQ) and the NDDI-E were performed for external validity. Data were compared between PWE with/without GAD using Chi 2 test and Student's t-test. Internal structural validity, external validity, and receiver operator characteristics were analyzed. A principal component factor analysis with Varimax rotation was performed on the 13 items of the GAD-7 (7 items) plus the NDDI-E (6 items). Results Testing was performed on 145 PWE: mean age = 39.38 years old (SD = 14.01, range: 18–75); 63.4% (92) women; 75.9% with focal epilepsy. Using the MINI, 49 (33.8%) patients had current GAD. Cronbach's alpha coefficient was 0.898, indicating satisfactory internal consistency. Correlation between GAD-7 and the PSQW scores was high (r (145) = .549, P  Significance This study validates the French language version of the GAD-7 screening tool for generalized anxiety in PWE, with a cutoff score of 7/21 for GAD, and also confirms that the GAD-7 is a short and easily administered test. Factor analysis shows that the GAD-7 (screening for generalized anxiety disorder) and the NDDI-E (screening for major depression) provide complementary information. The routine use of both GAD-7 and NDDI-E should be considered in clinical evaluation of patients with epilepsy.