People around the world experienced an increase in loneliness during the COVID-19 pandemic, which, although small, could have implications for people's long-term mental and physical health, longevity, and well-being, according to research published by the American Psychological Association.

"The pandemic does appear to have increased loneliness," said study lead author Mareike Ernst, PhD, of Johannes Gutenberg-University Mainz in Germany. "Given the small effect sizes, dire warnings about a 'loneliness pandemic' may be overblown. However, as loneliness constitutes a risk for premature mortality and mental and physical health, it should be closely monitored. We think that loneliness should be made a priority in large-scale research projects aimed at investigating the health outcomes of the pandemic."

The research was published in the journal American Psychologist.

Ernst and her coauthors wanted to explore whether changes such as lockdowns, physical distancing, and the switch to remote work and school during the pandemic increased people's loneliness. Such measures undoubtedly increased social isolation, but research has found that social isolation does not always lead to loneliness. Social isolation means having a small social network and few interactions with others, while loneliness is the painful feeling of having less or poorer quality social connections than a person wants. Some studies have found only weak correlations between the two.

To figure out whether the pandemic actually increased loneliness, the researchers reviewed 34 studies from four continents—primarily in North America and Europe—involving more than 200,000 total participants. All of the data came from long-term studies that measured participants' levels of loneliness before the onset of the pandemic and again during the pandemic. The researchers found a small but significant increase in loneliness during the pandemic—about a 5% increase in the prevalence of loneliness across the individual studies, on average. However, not all groups experienced that increase.

More research is needed on the factors that put some individuals and groups at higher risk of experiencing loneliness, whether the changes in loneliness were primarily due to alterations in the quality or the quantity of people's social interactions, and whether those differed across subpopulations, such as students and older adults. Such studies could help researchers develop better targeted interventions to increase people's amount of social interaction or to improve the quality of their close relationships.

"Strong evidence supporting interventions addressing loneliness remains limited. The increase in loneliness associated with the pandemic highlights the need for a concerted effort to strengthen that evidence base," Ernst said.

Because the majority of the studies in this review came from high- and upper-middle-income countries, further research should also investigate whether the pandemic has led to an increase in loneliness in the low- and middle-income countries as well, according to the researchers.