About a third of Canadians feel lonely, and a study from the University of Waterloo shows it has a greater negative impact on memory than even social isolation, though both present a significant risk to the aging population.

Loneliness is a subjective emotion that people might feel even while engaging in social activities. It is often associated with depression and an increase in stress hormones that may contribute to impaired memory.

Waterloo researchers examined four combinations of social isolation and loneliness and their effect on memory in middle-aged and older adults over a six-year period. These combinations include being socially isolated and lonely, being only socially isolated, being only lonely and being neither.

“As we expected, people who were both socially isolated and lonely had the greatest decline in memory, which intensified over the six years,” said Ji Won Kang, lead author on the paper and a PhD candidate in the School of Public Health Sciences at Waterloo. “But we were surprised to find that loneliness alone had the second-greatest impact on memory, even though so many studies report on the dangers of social isolation without considering loneliness.”

Those who aren’t lonely but are socially isolated may be stimulating their mental capacity with solo activities, such as reading, playing games and engaging in hobbies that improve memory and stimulate the brain, despite not engaging in social activities.

Kang hopes the findings of this research will highlight the need for community programs, especially for the combined group of older adults who are both socially isolated and lonely, and therefore at the highest risk of memory impairment.

“Older adults in the lonely category often have lower incomes than the other groups and may have structural barriers and health conditions preventing them from connecting to their communities,” she said. “A solution could be to implement transportation or home-visit programs — something to address the societal issues that lead to them being more isolated.”

The group who is just lonely is the next priority, requiring a different approach.

“We would need to know what is causing their loneliness,” Kang said. “They may be connected socially and have close relationships, but for example, maybe their marriage is falling apart and they would benefit from counselling.”

The study was an interdisciplinary project between the School of Public Health Sciences and the Department of Statistics and Actuarial Science at Waterloo. Exploring the differential impacts of social isolation, loneliness, and their combination on the memory of an aging population: A 6-year longitudinal study of the CLSA appears in the Archives of Gerontology and Geriatrics.