Prevalence of Depression in Alzheimer's Disease and Validity of Research Diagnostic Criteria

This study was undertaken to estimate the point-prevalence of Research Diagnostic Criteria (RDC) depressive syndromes in Alzheimer's disease (AD) and to evaluate the validity of existing and potential alternative diagnostic criteria for major depression in the presence of probable AD. Twenty-six subjects with probable AD of mild to moderate severity and their caregivers were interviewed to estimate the prevalence of RDC depressive syndromes. For the evaluation of the validity of RDC for major depression, an additional 8 probable-AD subjects with suspected depression were added to the sample. Sensitivity, specificity, and correlation with diagnosis of RDC major depression were calculated for each diagnostic criterion, and existing major depressive criteria were compared to potential alternative criteria currently used for RDC minor depression. Of the subjects in our prevalence sample, 15.4% were found to have major depression; 23.1%, minor depression; and 11.5%, intermittent depression. In our validation s...