Cognitive function following SARS-CoV-2 infection in a population-representative Canadian sample

BACKGROUND: SARS-CoV-2 infection is believed to adversely affect the brain, but the degree of impact on socially relevant cognitive functioning and decision-making is not well-studied, particularly among those less vulnerable to age-related mortality. The current study sought to determine whether infection status and COVID-19 symptom severity are associated with cognitive dysfunction among young and middled-aged adults in the general population, using self-reported lapses in executive control and a standardized decision-making task. METHOD: The survey sample comprised 1958 adults with a mean age of 37 years (SD ​= ​10.4); 60.8% were female. Participants reported SARS-CoV-2 infection history and, among those reporting a prior infection, COVID-19 symptom severity. Primary outcomes were self-reported symptoms of cognitive dysfunction assessed via an abbreviated form of the Barkley Deficits in Executive Functioning Scale (BDEFS) and performance on a validated delay-discounting task. RESULTS: Young and middle-aged adults with a positive SARS-CoV-2 infection history reported a significantly higher number of cognitive dysfunction symptoms (M(adj) ​= ​1.89, SE ​= ​0.08, CI: 1.74, 2.04; n ​= ​175) than their non-infected counterparts (M(adj) ​= ​1.63, SE ​= ​0.08, CI: 1.47,1.80; n ​= ​1599; β ​= ​0.26, p ​= ​.001). Among those infected, there was a dose-response relationship between COVID-19 symptom severity and level of cognitive dysfunction reported, with moderate (β ​= ​0.23, CI: 0.003–0.46) and very/extremely severe (β ​= ​0.69, CI: 0.22–1.16) COVID-19 symptoms being associated with significantly greater cognitive dysfunction. These effects remained reliable and of similar magnitude after controlling for demographics, vaccination status, mitigation behavior frequency, and geographic region, and after removal of those who had been intubated during hospitalization. Very similar—and comparatively larger—effects were found for the delay-discounting task, and when using only PCR confirmed SARS-CoV-2 cases. CONCLUSIONS: Positive SARS-CoV-2 infection history and moderate or higher COVID-19 symptom severity are associated with significant symptoms of cognitive dysfunction and amplified delay discounting among young and middle-aged adults with no history of medically induced coma.