The Impact of Loneliness and Social Isolation on Cognitive Aging: A Narrative Review

Social concepts such as loneliness and social isolation are fairly new factors that have been recently gaining attention as to their involvement in changes in cognitive function and association with dementia. The primary aim of this narrative review was to describe the current understanding of how loneliness and social isolation influence cognitive aging and how they are linked to dementia. Studies have shown that there is an association between loneliness, social isolation, and reduced cognitive function, in older adults, across multiple cognitive domains, as well as a heightened risk of dementia. Numerous changes to underlying neural biomechanisms including cortisol secretion and brain volume alterations (e.g., white/grey matter, hippocampus) may contribute to these relationships. However, due to poor quality research, mixed and inconclusive findings, and issues accurately defining and measuring loneliness and social isolation, more consistent high-quality interventions are needed to determine whether studies addressing loneliness and social isolation can impact longer term risk of dementia. This is especially important given the long-term impact of the COVID-19 pandemic on social isolation in older people is yet to be fully understood.