Hospital Anxiety and Depression (HAD) scale: factor structure, item analyses and internal consistency in a large population.
BACKGROUND
The Hospital Anxiety and Depression (HAD) rating scale is a commonly used questionnaire. Former studies have given inconsistent results as to the psychometric properties of the HAD scale.


OBJECTIVE
To examine the psychometric properties of the HAD scale in a large population.


METHODS
All inhabitants aged 20-89 years (n=92 100) were invited to take part in The Nord-Trøndelag Health Study, Norway. A total of 65 648 subjects participated, and only completed HAD scale forms (n=51 930) formed the basis for the psychometric examinations.


RESULTS
Principal component analysis extracted two factors in the HAD scale that accounted for 57% of the variance. The anxiety and depression sub-scales shared 30% of the variance. Both subscales were found to be internally consistent, with values of Cronbach's coefficient (alpha) being 0.80 and 0.76, respectively.


CONCLUSIONS
Based on data from a large population, the basic psychometric properties of the HAD scale as a self-rating instrument should be considered as quite good in terms of factor structure, intercorrelation, homogeneity and internal consistency.
Mykletun
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Faculty of Psychology, University of Bergen, Bergen, Norway.
Stordal
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Dahl
A A
AA
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001008:Anxiety Disorders / Q000175:diagnosis; D003866:Depressive Disorder / Q000175:diagnosis; D005260:Female; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis*; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D011594:Psychometrics; D015203:Reproducibility of Results