During the early days of the pandemic, Anthony Ong, professor of psychology, made a curious observation: Some of his friends were thriving in isolation. Yet others have felt lonely even when surrounded by others.

Ong, who is also professor of gerontology in medicine at Weill Cornell Medicine, knew that loneliness and isolation had negative health effects, including on cognition, and that older adults were especially at risk. Some studies had investigated whether loneliness or isolation mattered more for cognitive health, with mixed results. But he wanted to ask a deeper question: When there’s a mismatch between how lonely someone feels and how isolated they are objectively, how does that affect cognitive decline over time? Would those who felt lonely even when they had more social interactions be more vulnerable than those who were isolated but content? 

Those are the questions that Ong and collaborators from Northwestern University are exploring thanks to a $2.5 million grant from the National Institutes of Health. The researchers will analyze 11 existing data sets from the US and Europe that asked more than 70,000 older adults about their social contacts and feelings of loneliness, as well as assessing their cognitive abilities, over long periods of time.

“We think people who are high in isolation but low in loneliness are going to be relatively resilient — they may be content being alone,” Ong said. “However, we  predict that people who are around others but nonetheless feel profoundly lonely represent an at-risk group for  cognitive  impairment. Despite social contact, their social needs likely remain unfulfilled.”

Ong speculates that there are several reasons loneliness could be so pernicious even among those who are relatively connected. “Loneliness induces chronic stress, deterring self-care and impeding positive health behaviors," he explained. "Those lonely despite physical proximity also exhibit heightened vigilance to social threats and poorer coping capacities. Additionally, loneliness elevates cortisol, eliciting physiological changes affecting long-term wellness."

Since some of the studies Ong’s team is analyzing extended into 2020 and beyond, part of their research will examine how social distancing measures affected loneliness, isolation and cognitive decline. Another goal of the coordinated analysis is to see whether findings replicate across studies and which factors — such as cultural context or population density — may account for differences. 

While self-reported measures leave some subjectivity, Ong believes capturing lived experiences remains critical. "Though we can quantify physical contacts, individuals may still feel disconnected," Ong explained. "Perceived isolation matters; focusing exclusively on visible social interactions misses psychological distress sealing individuals off, even if surrounded by others."

Ong points out that loneliness itself is not the problem. “Acute feelings of loneliness signal our fundamental need for meaningful bonds. Feeling lonely prompts awareness that our social surroundings fail to nourish us psychologically. Thus, fleeting loneliness is adaptive, preserving well-being through driving reconnection. However, unattended distress escalating into chronic, toxic loneliness can inflict damage across physical and mental functioning.”