Loneliness and social isolation during the COVID-19 pandemic: A systematic review enriched with empirical evidence from a large-scale diary study

The outbreak of the global COVID-19 pandemic has drastically altered people’s lives. Loneliness and social isolation were publicly discussed as possible psychological consequences of the measures taken to slow the virus spread. These public discussions have sparked a surge in empirical studies on loneliness and social isolation. In this study, we first provide a systematic review synthesizing recent literature on the prevalence and correlates of loneliness and social isolation during the early phase of the COVID-19 pandemic (k = 53 studies). We found that most quantitative studies included in the systematic review were cross-sectional. The few longitudinal studies mainly reported increases in loneliness, especially when the pre-pandemic measurement occasions were months or years before the COVID-19 pandemic. Studies with pre-pandemic measures weeks or days before the pandemic reported relatively stable or even decreasing loneliness trends. Second, we enrich the systematic review with an empirical investigation on daily changes in the perceived quality and quantity of social relationships during the pandemic compared to before the pandemic (N = 4,823). This empirical investigation showed that, on average, the quality of social relationships was perceived worse during the pandemic than before. This perception got slightly stronger over the first two weeks of the pandemic but stagnated thereafter. Regarding the quantity of social relationships, participants reported on average that they had fewer social interactions at the beginning of the study than before the pandemic. This perceived reduction in the quantity of social interactions linearly decreased over time.