Chronic loneliness may harm cognitive health in young adults

UNIVERSITY PARK, Pa. — Young and middle-aged adults who live with chronic loneliness may be at risk for early cognitive decline, according to a new study by researchers in the Penn State Department of Human Development and Family Studies.

In a study published in BMC Public Health, the researchers demonstrated that young and middle-aged adults with chronic loneliness did not show improvements on cognitive assessments, while their peers who were not chronically lonely did improve on those same assessments.

“Loneliness is natural and a universal experience, but once it becomes chronic, it can take a toll on your cognitive health,” said Jee eun Kang, lead author of the study and postdoctoral scholar in the Penn State Center for Healthy Aging. 

The researchers analyzed data collected from 172 participants, aged 25 to 65 years, in the Effects of Stress on Cognitive Aging, Physiology and Emotion (ESCAPE) Project. The data, collected from each participant three times over a two-year period at one-year intervals, included measures of loneliness, working memory, processing speed and spatial memory. At each wave, cognitive abilities were measured using a mobile phone app and packaged as “brain games.” The participants played the games five times per day for two weeks.

In the study, loneliness was defined as the perceived gap between a desired relationship and the actual social relationship in both quantity and quality.

Loneliness was measured using a paper-and-pencil survey where participants responded to statements like “I feel left out” on a scale from one to five, with one representing “Never” and five representing “Very Often.” People were identified as chronically lonely if they scored within the highest group of the scale in at least two consecutive waves. 

The researchers found participants with chronic loneliness did not exhibit practice-related improvements in the brain games, while those without chronic loneliness exhibited significant practice-related improvements.

“Anytime we conduct a research study where we repeatedly measure cognitive abilities, there is this tendency for participants to continually get a little bit better because they become familiar with the skills needed on the test,” said Martin Sliwinski, co-author of the study and director of the Penn State Center for Healthy Aging. “In this study, people played the games multiple times each day. It is no surprise that the performance of the average person improved.”

The surprise, Sliwinski said, was that the performance of those who were chronically lonely did not improve. The lack of practice-related improvement demonstrated poorer cognitive function, according to the researchers, who warned chronic loneliness earlier in life may indicate risk for more pronounced cognitive decline later in life.

“In studies of much older people, those who do not improve in cognitive assessments are more likely to have early neurodegenerative conditions,” said Sliwinski, who is also a professor of human development and family studies at Penn State. “Our findings demonstrate a lack of improvement in retest-related assessments, so we are thinking chronic loneliness may be an early risk factor for neurodegeneration — though more research would be needed to confirm that hypothesis.”

The study is one of the first to use longitudinal measurements — measures that track the same individuals over a period of time — to establish the effects of loneliness over time on young and middle-aged adults. The researchers said their results demonstrate the importance of preserving cognitive health and establishing habits as young and middle-aged adults that can lay the foundation for their lives as older individuals.

“It is never too late to save for retirement, but if you start saving for retirement at age 70, you are going to have a harder time than if you start investing in your financial future when you are young,” Sliwinski said. “It is the same with investing in your cognitive and social health when you are young. If you invest earlier, you are going to have an easier time as you get older.” 

Combating loneliness can be challenging for young and middle-aged adults because social structures and methods of connection constantly change. The researchers said intentionality — like scheduling time with others or being present during social interactions — is the best strategy for young and middle-aged adults to address chronic loneliness and prevent its unfavorable cognitive effects. 

Loneliness can serve as a signal to make more social connections or ask for help in forming social relationships to sustain positive cognitive function, according to Kang. 

“Chronically lonely people are more socially anxious or have negative interpretations of their social relationships,” Kang said. “It may be harder for them to take the first steps in building connections, but social support is essential in reducing loneliness. For those who are lonely, do not be afraid to reach out to others. Even if it is difficult, it is an important life skill to develop for your quality of life and cognitive health.” 

The National Institutes of Health’s National Institute on Aging (NIA) offers tips for connecting with others for older adults that can also serve younger individuals, according to the researchers.

Lynn Martire, professor of human development and family studies; Jennifer Graham-Engeland, professor of biobehavioral health; and David Almeida, professor of human development and family studies, also contributed to this research.

The NIA helped support this research project. 

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