An analysis of people hospitalized with COVID-19 during the first wave of the pandemic has shown that their ongoing cognitive decline is equivalent to losing 10 IQ points.
The cognitive abilities of people who were hospitalised with covid-19 during the first wave of the pandemic remain lower than expected, even years later, and there is some evidence that this is forcing them to change jobs.
“What we found is that the average cognitive deficit was equivalent to 10 IQ points, based on what would be expected for their age, et cetera,” says Maxime Taquet at the University of Oxford.
His team examined 475 individuals in the UK who had been hospitalized with COVID-19 and discharged before 31 March 2021. All participants had completed psychiatric and cognitive assessments six months after their discharge as part of another study. Taquet’s team asked them to repeat the assessments two to three years later and found that, on average, symptoms of depression, anxiety, and fatigue had worsened. “More people are getting worse than getting better,” says Taquet.
Overall, 47% of participants had moderate to severe depression at the second assessment, compared to 34% at six months. Similarly, 40% experienced moderate to severe fatigue, up from 26% in the initial tests. The proportion of individuals with moderate to severe anxiety saw a smaller increase, rising from 23% to 27%.
The reasons for the worsening symptoms are unclear, but the team found that those with more severe symptoms initially were more likely to see them intensify over time. Taquet noted that one participant mentioned it was difficult to be short of breath for three years without experiencing depression.
The team also discovered that over a quarter of participants had changed their occupation since being hospitalized, with half of those citing poor health as the reason. The researchers found a strong link between changing occupation and cognitive decline, but not with depression, anxiety, or fatigue. This suggests that many individuals are changing jobs because they can no longer handle the cognitive demands of their previous roles, rather than due to a lack of energy or interest, according to Taquet.
He acknowledges that the study has significant limitations. Only a fifth of those invited to participate did so, raising questions about the study’s representativeness. Additionally, since participants were not tested before hospitalization, there is no baseline for comparison, notes team member Paul Harrison, also at the University of Oxford. Instead, the conclusion that participants lost an average of 10 IQ points is based on expected norms for people of the same age, sex, and education level, as determined by the Great British Intelligence Test.
Journal reference: Lancet Psychiatry DOI: S2215-0366(24)00214-1