Constantly worrying about the coronavirus pandemic not only stresses you out, but can impair your cognitive abilities as well, a new study warns. Researchers from McGill University found that people dwelling on pandemic-related fears made poorer choices, miscalculated the risks of certain outcomes, and displayed slower mental processing speed.

The McGill team worked with The Neuro (Montreal Neurological Institute-Hospital) to survey over 1,500 Americans between April and June 2020 to see how pandemic fears affected their thinking. Participants had to rate their level of worry concerning COVID-19 before completing a series of psychological and cognitive tests. These exams measured how well each person processed certain situations and remembered important pieces of information to complete a task. Afterwards, researchers compared the results to the same tests conducted prior to the pandemic.

For the tests examining how well people maintain information, participants had to match pairs of numbers and symbols according to a specific set of rules. Study authors also examined the group’s decision-making skills using a test of risk management. Each person could either choose a “certain” option where they definitely won $75, or a “risky” option where the odds of winning $0 were only 25 percent and the odds of winning $100 were 75 percent.

Results of these tests show people experiencing higher levels of pandemic-related worry displayed lower information processing speed and less ability to retain important information. They also had a higher degree of sensitivity to the odds that bad things might happen.

Pandemic decision making in doubt

People taking the tests during the pandemic performed poorly on simple cognitive tests in comparison to the pre-pandemic group. Moreover, Americans in the last wave of test-takers showed even slower mental processing speeds than those in the first wave.

The team also discovered that worrying about COVID-related issues distorted a person’s ability to evaluate certain risks. They underestimated the chances of likely outcomes occurring (like winning $100) and overestimated the chances of unlikely possibilities occurring (like winning nothing at all). The team believes this impact on decision-making abilities may influence some people when they’re considering certain topics — like getting the COVID-19 vaccine.