6 Depressive Symptoms are Associated With Decline Over Time in Verbal Fluency Performance in Female but not Male Community-Dwelling Older Adults

Abstract

Objective:Late-life depression is prevalent among older adults and the presence of depressive symptoms has been shown to be associated cross-sectionally with worse verbal fluency performance. There is limited and mixed evidence as to whether depressive symptoms impact change in verbal fluency performance over time, and whether gender impacts this relationship.Participants and Methods:Participants were community-dwelling older adults who were dementia-free at baseline (N = 522; M age = 75.96, SD + 6.46 years). Baseline depressive symptoms were measured using the Geriatric Depression Scale. Category fluency and letter fluency performance, using the Controlled Oral Word Association Test (COWAT), were examined annually. Linear mixed effects models stratified by gender examined whether associations between baseline depressive symptoms and changes in fluency performance over five years were different in female (n = 289) as compared to male (n = 233) participants. Sensitivity analyses excluding participants with prevalent or incident mild cognitive impairment (MCI) (n = 141), excluding participants with incident dementia (n = 28), and excluding participants with prevalent or incident MCI or incident dementia (n = 169) were run. All analyses were adjusted for age, years of education, estimated premorbid functioning, and health comorbidities.Results:Depression was minimal across participants (m = 4.72, SD + 3.96). A subset of participants (n = 44) reported “possible depression,” namely levels suggestive of subclinical depression, according to clinical cutoffs. The “possible depression” group included 31 females (10.73% of females) and 13 males (5.58% of males), and the “no depression” group included 258 females (89.27% of females) and 220 males (94.42% of males). Baseline levels of depressive symptoms suggestive of subclinical depression were associated with worse decline in category fluency performance during longitudinal follow-up in females (estimate = -0.16, p = .002) but not males (estimate = -0.03, p = .658). Results remained the same when excluding prevalent and incident MCI cases (estimate = -0.19, p = .005), excluding incident dementia cases (estimate = -0.12, p = .017), and excluding prevalent and incident MCI and incident dementia cases (estimate = -0.20, p = .004). Letter fluency performance did not decline over time and was not influenced by levels of depressive symptoms in females (estimate = -0.03, p = .502) or males (estimate = 0.05, p = .452).Conclusions:Baseline presence of depressive symptoms suggestive of subclinical depression was associated with worse decline in category fluency performance during longitudinal follow-up in female but not male participants. Letter fluency performance did not decline and was not impacted by levels of depressive symptoms. Results remained significant when accounting for covariates and potential confounders. The present study elucidated the combined influence of gender and depressive symptoms on change in fluency performance in older adults and can aid in identifying individuals who may be at a greater risk of cognitive decline.