Associations between depression symptoms and executive function in older adults with mild cognitive impairment: One‐year follow‐up

Abstract

AbstractBackgroundPsychiatric disorders are among etiologies for Mild Cognitive Impairment (MCI), one of the main one is depression. The relationship between depression and Alzheimer's disease (AD) is not yet fully understood and it is considered both, isolated risk factor and prodrome stage of AD. The aim of this work is to investigate if older adults with MCI associated with significant depressive symptoms, compared with those without these symptoms, will have different executive functions outcomes after one‐year follow‐up.MethodRepeated measures ANCOVA with Bonferroni post‐hoc analysis was used with cognitive variables at baseline and follow up evaluation as dependent, presence of significative depression symptoms at baseline as independent while controlling for covariates age, gender and years of formal education. Depressive symptoms were measured by 15‐item geriatric depression scale and the cutoff point was 6. Executive functions as inhibitory control e cognitive flexibility were assessed by Five Digit Test, working memory by Digit Span Test and phonemic verbal fluency by letter S. Patients started depression treatment at baseline.ResultWere included 170 participants (125 without depressive symptoms and 45 with symptoms), mean age 74.44, 68 women, mean years of formal education was 4,54. Among these, 99 (29 with depressive symptoms) complete all tests in the two assessments. Due to cognitive impairment, some of them were unable to even start cognitive flexibility test. Results indicated there was a significant effect of depression symptoms at baseline on cognitive flexibility ability [F (1.94) = 7,271, p = 0.008). Participants with depression presented a significant improvement (p = 0.006) on cognitive flexibility average from baseline (11.60) to the end of follow up (7.24). For those without symptoms of depression at baseline, the averages were 6.32 at baseline and 5.98 at follow‐up. There was no significant effect of depressive symptoms on the other cognitive skills assessed when considering these covariates.ConclusionComparing participants with and without depression symptoms at baseline, there was an improvement in cognitive flexibility in the former group. We think this result could be related to effect of depression treatment.