Stress is thought to exacerbate cognitive decline in older adults, especially those with late life depression (LLD); however, the specific aspects of stress that are especially deleterious and the aspects of cognition they affect are not clear. For example, it is not known whether the effects result from the exposure to stressful life events or whether it is the perception of stress that is salient, and whether these relate to the domains of cognition affected.
We hypothesized that the number of stressful events and the magnitude of perceived stress in older adults with LLD at baseline would be associated with cognitive decline over 2 years.
lder adults (ages 60-90 years) with LLD (n=124, mean age 71.5 years) and never-depressed elderly healthy controls (HCs) (n=39, mean age 74.6 years) were assessed at three time points each one year apart for number of stressful life events within the prior year using the Duke Depression Evaluation Scale, and perceived stress within the prior six months, and with five neurocognitive tests that included the Trail Making (Trail Making B – Trail Making A), Benton Visual Retention Test, Symbol Digit Modalities Test (Processing Speed), Logical Memory Delayed Recall II and Consortium to Establish a Registry for Alzheimer’s Disease neuropsychological battery.
Associations were examined (Spearman correlations) between baseline measures of the number of stressful life events and the perception of stress with change in cognitive test performance over time from baseline to year 1 and to year 2. Associations between stress measures and changes in the cognitive measures were considered significant at p<0.05.
Only the LLD group showed a significant association between stress and cognitive changes. The level of perceived stress at baseline was associated with a decline on Trail Making from baseline to 1 year (r=0.22, pcorr=0.022); this association was stronger when assessed from baseline to 2 years (r=0.29, p=0.0058).
This study suggests that for older adults with LLD it was the perception of stress at baseline, not the number of stressful life events at baseline, that was associated with decline in executive functioning in the following 2 years. The findings highlight the importance of assessing the perception of stress in LLD, as individuals with LLD and high levels of perceived stress may be at risk for decline in executive functioning. Further study is warranted on adverse effects of perceived stress in LLD and the potential for preventing decline in executive functioning by reducing levels of perceived stress.