A reliability and validity study of the cornell scale among elderly inpatients, using various clinical criteria.

BACKGROUND

The validity of the Cornell Scale for Depression in Dementia is seldom studied in institutions.

METHOD

Two reliability studies, with 103 and 32 patients, and a validity study with 231 patients in nursing homes and in hospital were performed. They were assessed by the Cornell Scale, Clinical Dementia Rating scale and Self-Maintenance scale. A psychiatrist 'blind' to the Cornell assessment diagnosed depression according to the ICD-10, DSM-IV-TR and the Provisional Criteria for Depression in Alzheimer's Disease (PCD-dAD).

RESULTS

Cronbach's alpha values were 0.81 and 0.95, and the mean kappa for the Cornell items were 0.91 and 0.57, respectively. In the validity study, 164 subjects had dementia; 105 (45.5%) had depression according to the ICD-10, 68 (29.9%) according to the DSM-IV-TR and 88 (53.3%) of the demented patients had depression according to the PCD-dAD. In the receiver operating characteristic analysis, the DSM-IV-TR criteria produced the highest area under the curve, i.e. 0.81 (95% CI: 0.75-0.87). A range of cutoff points for a depressive disorder was found for the various clinical criteria.

CONCLUSION

The Cornell Scale is reliable and a range of cutoff points should be used for various clinical criteria of depression.