RESUMO
OBJECTIVE: Depression and cognitive impairment are closely associated in old age. In this study, we investigate the influence of depression on the prediction accuracy of Mini-Mental State Examination (MMSE) as screening test for early detection of dementia. METHODS: Three hundred and twenty one dementia patients and five hundred and thirty five normal control subjects were enrolled in this study. We administered both the Mini International Neuropsychiatric Inventory and the Korean version of the Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet clinical and neuropsychological battery. We diagnosed depressive disorders according to the Diagnostic and Statistical Manual of Mental Disorders, fourth edition diagnostic criteria, and evaluated the severity of depressive symptoms using the revised Korean version of the Geriatric Depression Scale. Subjects were divided into two groups : 1) depressed group, 2) non-depressed group. We compared sensitivity, specificity, positive predictive value, negative predictive value, receiver operating characteristic curve, and areas of under the curve (AUC) of MMSE between two groups. RESULTS: AUC of total group was 0.803 [95% confidence interval (CI)=0.774-0.833]. AUC of non-depressed group was the higher (0.855 ; 95% CI=0.823-0.887) than that of depressed group (0.767 ; 95% CI=0.710-0.824, p<0.009). CONCLUSION: In non-depressed group, diagnostic accuracy and positive predictive value were higher than those of depressed group. Depression should be considered for effective and efficient national dementia screening and registry program.