title: 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<.0001), indicating good external validity. Factor analysis shows that the anxiety investigated with the GAD-7 and depression investigated with the NDDI-E reflect distinct factors. Receiver operator characteristic analysis showed area under the curve of 0.899 (95% CI 0.838-0.943, P < 0.0001) indicating good capacity of the GAD-7 to detect GAD (defined by MINI). Cutoff for maximal sensitivity and specificity was 7. Mean GAD-7 score in PWE with GAD was 13.22 (SD = 3.99), and that without GAD was 5.17 (SD = 4.66).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Services d'explorations fonctionnelles du système nerveux, Clinique du sommeil, CHU de Bordeaux, Place Amélie Raba-Leon, 33076 Bordeaux, France; USR CNRS 3413 SANPSY, CHU Pellegrin, Université de Bordeaux, France.
authors.forename: Jean-Arthur
authors.initials: JA
authors.lastname: Micoulaud-Franchi
authors.affiliation: Service de Neurophysiologie Clinique, APHM, Hôpital de la Timone, 13005 Marseille, France.
authors.forename: Stanislas
authors.initials: S
authors.lastname: Lagarde
authors.affiliation: Hôpital Henri Gastaut, Etablissement Hospitalier Spécialisé dans le traitement des Epilepsies, 300 Boulevard de Sainte-Marguerite, 13009 Marseille, France.
authors.forename: Gérald
authors.initials: G
authors.lastname: Barkate
authors.affiliation: Service de Neurophysiologie Clinique, APHM, Hôpital de la Timone, 13005 Marseille, France.
authors.forename: Boris
authors.initials: B
authors.lastname: Dufournet
authors.affiliation: Hôpital Henri Gastaut, Etablissement Hospitalier Spécialisé dans le traitement des Epilepsies, 300 Boulevard de Sainte-Marguerite, 13009 Marseille, France.
authors.forename: Cyril
authors.initials: C
authors.lastname: Besancon
authors.affiliation: Service de Neurophysiologie Clinique, APHM, Hôpital de la Timone, 13005 Marseille, France; INSERM UMR 1106, INS, 27 Bd Jean Moulin, 13385 Marseille, France; Aix Marseille Université, Faculté de Médecine, Marseille, France.
authors.forename: Agnès
authors.initials: A
authors.lastname: Trébuchon-Da Fonseca
authors.affiliation: Service de Neurophysiologie Clinique, APHM, Hôpital de la Timone, 13005 Marseille, France; INSERM UMR 1106, INS, 27 Bd Jean Moulin, 13385 Marseille, France; Aix Marseille Université, Faculté de Médecine, Marseille, France.
authors.forename: Martine
authors.initials: M
authors.lastname: Gavaret
authors.affiliation: Service de Neurophysiologie Clinique, APHM, Hôpital de la Timone, 13005 Marseille, France; INSERM UMR 1106, INS, 27 Bd Jean Moulin, 13385 Marseille, France; Aix Marseille Université, Faculté de Médecine, Marseille, France; Hôpital Henri Gastaut, Etablissement Hospitalier Spécialisé dans le traitement des Epilepsies, 300 Boulevard de Sainte-Marguerite, 13009 Marseille, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Bartolomei
authors.affiliation: Service de Neurophysiologie Clinique, APHM, Hôpital de la Timone, 13005 Marseille, France; INSERM UMR 1106, INS, 27 Bd Jean Moulin, 13385 Marseille, France; Aix Marseille Université, Faculté de Médecine, Marseille, France.
authors.forename: Francesca
authors.initials: F
authors.lastname: Bonini
authors.affiliation: Service de Neurophysiologie Clinique, APHM, Hôpital de la Timone, 13005 Marseille, France; INSERM UMR 1106, INS, 27 Bd Jean Moulin, 13385 Marseille, France; Aix Marseille Université, Faculté de Médecine, Marseille, France. Electronic address: aileen.mcgonigal@univ-amu.fr.
authors.forename: Aileen
authors.initials: A
authors.lastname: McGonigal
mesh_terms: D000293:Adolescent; D000328:Adult; D001008:Anxiety Disorders / Q000175:diagnosis* / Q000523:psychology; D003865:Major Depressive Disorder / Q000175:diagnosis* / Q000523:psychology; D004827:Epilepsy / Q000523:psychology*; D005260:Female; D005602:France; D006801:Humans; D007802:Language; D008297:Male; D008875:Middle Aged; D010555:Personality Inventory; D011569:Psychiatric Status Rating Scales / Q000592:standards*; D011594:Psychometrics / Q000706:statistics & numerical data; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: Epilepsy; Generalized anxiety disorder; Psychiatric comorbidity; Reliability; Screening tool; Validity