The effects of anxiety, depression, and age on cognitive functions in older adults: A longitudinal study

During the last decade, the relationship between negative affect states and cognition in older adults has become a topic of tremendous research and clinical interest. Despite a steady growth of empirical investigation in this area, however, the long-term impact of depression and anxiety on neuropsychological function remains poorly understood. This dissertation investigated the hypothesis that anxiety and depression contribute to age-related cognitive decline in the areas of memory, executive function, and processing efficiency. The sample included 57 community-dwelling older adults between the ages of 57 and 92 (Time 1 M = 69.86, SD = 6.36 years; Time 2 M = 75.09, SD = 6.47 years). All variables were measured using standard neuropsychological tests of performance and a short demographic questionnaire. Mood was assessed using self-report measures, including the Beck Depression Inventory (BDI), Geriatric Depression Scale (GDS), and the State-Trait Anxiety Inventory (STAI). Subjects returned for follow-up evaluation approximately 5 years after initial participation. Results of repeated measures ANCOVA analyses revealed that higher levels of depressive symptomatology were not predictive of cognitive decline above and beyond that already accounted for by age alone. However, higher levels of trait anxiety were found to predict 9.9% (p < .05) of the decrement in free recall memory, 8.2% (p < .05) of the decline in semantic clustering, and 8.4% (p < .05) of the deterioration in executive functioning performance. Trait anxiety was not found to predict decline in processing efficiency. Overall, these findings are consistent with a small, but growing, literature demonstrating that trait anxiety is associated with poorer verbal learning and executive dysfunction. Results suggest that even subclinical levels of anxiety may interfere with neuropsychological performance and may exacerbate the cognitive decline associated with normal aging. These findings are discussed in light of their practical, theoretical, and methodological implications and in the context of suggestions for future research.