Latent structure of the Hospital Anxiety And Depression Scale: a 10-year systematic review.
OBJECTIVE
To systematically review the latent structure of the Hospital Anxiety and Depression Scale (HADS).


METHODS
A systematic review of the literature was conducted across Medline, ISI Web of Knowledge, CINAHL, PsycInfo and EmBase databases spanning articles published between May 2000 and May 2010. Studies conducting latent variable analysis of the HADS were included.


RESULTS
Twenty-five of the 50 reviewed studies revealed a two-factor structure, the most commonly found HADS structure. Additionally, five studies revealed unidimensional, 17 studies revealed three-factor, and two studies revealed four-factor structures. One study provided equal support for two- and three-factor structures. Different latent variable analysis methods revealed correspondingly different structures: exploratory factor analysis studies revealed primarily two-factor structures, confirmatory factor analysis studies revealed primarily three-factor structures, and item response theory studies revealed primarily unidimensional structures.


CONCLUSIONS
The heterogeneous results of the current review suggest that the latent structure of the HADS is unclear, and dependent on statistical methods invoked. While the HADS has been shown to be an effective measure of emotional distress, its inability to consistently differentiate between the constructs of anxiety and depression means that its use needs to be targeted to more general measurement of distress.
Department of Psychology, Division of Population Health Sciences, Royal College of Surgeons in Ireland, Ireland. theodorecosco@rcsi.ie
Theodore D
TD
Cosco
Frank
F
Doyle
Mark
M
Ward
Hannah
H
McGee
D001007:Anxiety / Q000175:diagnosis / Q000453:epidemiology; D015897:Comorbidity; D003710:Demography; D003863:Depression / Q000175:diagnosis / Q000453:epidemiology; D005163:Factor Analysis, Statistical; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D011569:Psychiatric Status Rating Scales; D011594:Psychometrics / Q000379:methods / Q000592:standards; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires / Q000592:standards; D014894:Weights and Measures / Q000592:standards