Older adults 65 and older are the fastest growing segment of the population. Rates of cognitive impairment increase in older adulthood and are associated with increased risk for nursing home placement, depression, mortality, lower life satisfaction, and caregiver stress. In addition, anxiety disorders and symptoms are the most prevalent psychiatric disorder other than cognitive impairment among older adults. Research has demonstrated that anxiety is associated with deficits in the cognitive domains of memory and processing speed. However, the direction of the relationship is not clear, as anxiety has been identified as a risk factor for deficits in memory and processing speed and deficits in these domains are also associated with increased anxiety. Despite the fact that these are commonly occurring problems later in life, no research has examined whether anxiety is a leading indicator of change in cognitive functioning or vice versa. Additionally, research has suggested that the same underlying biological process may be causing both increased emotional distress such as anxiety and cognitive decline later in life. We propose to examine archival data from 758 twin pairs from the Swedish Adoption/Twin Study of Aging to explore the association between cognitive functioning and anxiety over a span of 18 years using dual change score models. This newly developed structural equation modeling technique allows examination of the bi-directional relationship between anxiety and cognitive performance. We propose to conduct structural equation model testing to determine which of these relationships statistically best explain this association.
The second aim of the study is to examine the dynamics underlying the genetic covariance between trajectories for anxiety, memory, and processing speed with aging. This examination will allow us to determine whether a common set of genetic influences explain levels and change in both cognition and anxiety.
Cognitive impairment and anxiety commonly co-occur, are serious, disabling, and costly problems among older adults, and more research is needed to examine the association between the two. There is evidence to suggest that the same genetic influences may be contributing to both increased psychological distress and cognitive impairment later in life. In this study we propose to examine the longitudinal association between anxiety and cognitive performance, using newly developed dual change score (DCSM) structural equation modeling techniques, in 758 pairs of twins participating in the Swedish Adoption/Twin Study of Aging. Additionally, we plan to examine the extent to which genetic and environmental influences explain this association using biometric DCSM models.