title: Limited validity of the Hospital Anxiety and Depression Scale (HADS) in dementia: evidence from a confirmatory factor analysis.
abstract: The Hospital Anxiety and Depression Scale (HADS) is a well-validated, self-report measure of both anxiety and depression. It is frequently used with people with dementia. However, its structural validity has never been examined in this population. The current study used confirmatory factor analysis (CFA) to assess this.
  
  
  
  Baseline data from two intervention studies for people with mild to moderate dementia were combined (N = 268). CFA was used to test whether a one, two or three factor structure best fit the data. Indices of model misspecification were examined to test for poor quality items, and models re-specified accordingly. Finally, measurement invariance across gender and different levels of cognitive impairment was assessed.
  
  
  
  A one-factor structure did not fit the data. Two and three factor structures fitted the data equally well. Model fit was improved by removal of two items. Measurement invariance was adequate across gender, but poor across groups with differing levels of cognitive impairment.
  
  
  
  The HADS is acceptable and feasible but difficult to interpret in a dementia population. We suggest that it should be interpreted as measuring two separate factors of anxiety and depression and not one 'distress' factor. However, two items may need to be removed, affecting cut-off scores. Poor measurement invariance means the HADS may not be a good tool for measuring differences in anxiety and depression between those with mild and those with moderate cognitive impairment. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Research Department of Clinical, Educational and Health Psychology, University College London, London, UK.
authors.forename: Joshua
authors.initials: J
authors.lastname: Stott
authors.affiliation: Research Department of Clinical, Educational and Health Psychology, University College London, London, UK.
authors.forename: Aimee
authors.initials: A
authors.lastname: Spector
authors.affiliation: Institute of Mental Health, University of Nottingham, Nottingham, UK.
authors.forename: Martin
authors.initials: M
authors.lastname: Orrell
authors.affiliation: Research Department of Clinical, Educational and Health Psychology, University College London, London, UK.
authors.forename: Katrina
authors.initials: K
authors.lastname: Scior
authors.affiliation: Division of Psychology and Language Science, University College London, London, UK.
authors.forename: Joanne
authors.initials: J
authors.lastname: Sweeney
authors.affiliation: Research Department of Clinical, Educational and Health Psychology, University College London, London, UK.
authors.forename: Georgina
authors.initials: G
authors.lastname: Charlesworth
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001007:Anxiety / Q000453:epidemiology; D001008:Anxiety Disorders / Q000175:diagnosis*; D003704:Dementia / Q000523:psychology*; D003866:Depressive Disorder / Q000175:diagnosis*; D005163:Factor Analysis, Statistical; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales / Q000592:standards*; D011594:Psychometrics; D015203:Reproducibility of Results
keywords: HADS; Hospital Anxiety and Depression Scale; dementia; factor analysis; validity