The factor structure and factor stability of the hospital anxiety and depression scale in patients with cancer.

An exploratory factor analysis of the HAD was carried out in 568 cancer patients. Two distinct, but correlated, factors emerged which corresponded to the questionnaire's anxiety and depression subscales. The factor structure proved stable when subsamples of the total sample were investigated. The internal consistency of the two subscales was also high. These results provide support for the use of the separate subscales of the HAD in studies of emotional disturbance in cancer patients.