Mental health and cognitive outcomes in patients six months after testing positive compared with matched patients testing negative for COVID-19 in a non-hospitalized sample: A prospective cohort study

Abstract Background: Most research on the psychiatric and cognitive outcomes of COVID-19 infection have been in patients who have been hospitalised, despite more than 95% of cases never being admitted to hospital. We aimed to determine the mental health and cognitive outcomes at six months of people who had not been hospitalized with COVID-19 and who had tested positive and negative for COVID-19 in Eastern Ontario. Methods: Participants were matched 1:1 at the 6-month time point. Primary analyses compared COVID-positive with matched COVID-negative participants. In addition, within the COVID-19 positive population, we used an age and sex-adjusted logistic regression analysis to explore risk factors associated with depression, anxiety, and cognitive impairment. Results: 324 participants were enrolled (n=162 per arm). 40.7% of those in the COVID-positive group were men, with an average age of 37.9 (SD 13.2) years of age. In the COVID-negative group 41.4% were men, with an average of 36.7 (SD 12.8) years of age. There were no statistically significant differences in mental health outcomes between the two groups. On cognitive testing, 21% of the COVID-positive participants and 14% of the COVID-negative participants scored below the cut off for significant cognitive impairment. Risk factors for poor mental and cognitive outcomes differed between the two groups. Conclusion: In non-hospitalised patients who have tested positive for COVID-19 there is no evidence of an increase in mental health disorders compared to people who tested negative. Any increases in mental health disorders during the pandemic are probably the effect of social changes rather than an effect of the virus itself. The exception may be the cognitive changes in those who tested positive.