Background: There are few studies on validation of depression scales in the elderly in Latin America. This study aimed to assess the validity of Montgomery-Åsberg. Depression Rating Scale (MADRS) and Cornell Scale for Depression in Dementia (CSDD) in Brazilian elderly outpatients.

Methods: A convenience sample of 95 outpatients was diagnosed for dementia and depression according to DSM-IV-TR, ICD-10, and PDC-dAD criteria. Receiver Operating Curves (ROC) were used to calculate the area under the curve (AUC) and to assess MADRS and CSDD cut-offs for each diagnostic criterion.

Results: Dementia was diagnosed in 71 of 95 patients. Depression was diagnosed in 35, 30, and 51 patients by ICD-10, DSM-IV, and PDC-dAD, respectively. MADRS cut-off score of 10 correctly diagnosed 67.4% and 66.3% patients as depressed according to DSM-IV and ICD-10. A cut-off of 9 correctly identified 74.7% by PDC-dAD criteria; a CSDD cut-off score of 13 best recognized depression according to DSM-IV and ICD-10. A score of 11 diagnosed depression according to PDC-dAD, while MADRS = 9 recognized depression in dementia. CSDD was more efficient in showing depression in mild than in moderate/severe dementia according to DSM-IV/ICD-10. PDC-dAD behaved nicely for any severity stage.

Conclusion: MADRS and CSDD cut-offs of 10 and 13 were the optimal ones to diagnose depression in elderly, respectively. CSDD cut-offs are higher than those found in other countries. Other Latin American studies are needed to compare results with our study.