title: The 7-item generalized anxiety disorder scale as a tool for measuring generalized anxiety in multiple sclerosis.
abstract: BACKGROUND
  Generalized anxiety disorder (GAD) is common in multiple sclerosis (MS) but understudied. Reliable and valid measures are needed to advance clinical care and expand research in this area. The objectives of this study were to examine the psychometric properties of the 7-item Generalized Anxiety Disorder Scale (GAD-7) in individuals with MS and to analyze correlates of GAD.
  
  
  METHODS
  Participants (N = 513) completed the anxiety module of the Patient Health Questionnaire (GAD-7). To evaluate psychometric properties of the GAD-7, the sample was randomly split to conduct exploratory and confirmatory factor analyses.
  
  
  RESULTS
  Based on the exploratory factor analysis, a one-factor structure was specified for the confirmatory factor analysis, which showed excellent global fit to the data (χ(2) 12 = 15.17, P = .23, comparative fit index = 0.99, root mean square error of approximation = 0.03, standardized root mean square residual = 0.03). The Cronbach alpha (0.75) indicated acceptable internal consistency for the scale. Furthermore, the GAD-7 was highly correlated with the Hospital Anxiety and Depression Scale-Anxiety (r = 0.70). Age and duration of MS were both negatively associated with GAD. Higher GAD-7 scores were observed in women and individuals with secondary progressive MS. Individuals with higher GAD-7 scores also endorsed more depressive symptoms.
  
  
  CONCLUSIONS
  These findings support the reliability and internal validity of the GAD-7 for use in MS. Correlational analyses revealed important relationships with demographics, disease course, and depressive symptoms, which suggest the need for further anxiety research.
authors.affiliation: Department of Rehabilitation Medicine, University of Washington School of Medicine, Seattle, WA, USA (ALT, NH, MB, RS, KA); and Veterans Affairs Puget Sound Health Care System, Multiple Sclerosis Center of Excellence West, Seattle, WA, USA (NH).
authors.forename: Alexandra L
authors.initials: AL
authors.lastname: Terrill
authors.affiliation: Department of Rehabilitation Medicine, University of Washington School of Medicine, Seattle, WA, USA (ALT, NH, MB, RS, KA); and Veterans Affairs Puget Sound Health Care System, Multiple Sclerosis Center of Excellence West, Seattle, WA, USA (NH).
authors.forename: Narineh
authors.initials: N
authors.lastname: Hartoonian
authors.affiliation: Department of Rehabilitation Medicine, University of Washington School of Medicine, Seattle, WA, USA (ALT, NH, MB, RS, KA); and Veterans Affairs Puget Sound Health Care System, Multiple Sclerosis Center of Excellence West, Seattle, WA, USA (NH).
authors.forename: Meghan
authors.initials: M
authors.lastname: Beier
authors.affiliation: Department of Rehabilitation Medicine, University of Washington School of Medicine, Seattle, WA, USA (ALT, NH, MB, RS, KA); and Veterans Affairs Puget Sound Health Care System, Multiple Sclerosis Center of Excellence West, Seattle, WA, USA (NH).
authors.forename: Rana
authors.initials: R
authors.lastname: Salem
authors.affiliation: Department of Rehabilitation Medicine, University of Washington School of Medicine, Seattle, WA, USA (ALT, NH, MB, RS, KA); and Veterans Affairs Puget Sound Health Care System, Multiple Sclerosis Center of Excellence West, Seattle, WA, USA (NH).
authors.forename: Kevin
authors.initials: K
authors.lastname: Alschuler