A long bout of Covid could cause patients’ IQs to drop by six points, a major study suggests.
Researchers in Britain found the loss for patients who said they had been suffering from Covid symptoms for more than 12 weeks, compared to those who said they had never had the virus.
They also calculated a loss of three IQ points among those who said they had Covid symptoms for 12 weeks, and of nine IQ points for those who were admitted to ICU during their infection, compared with those who said they had not were infected.
Experts suggested that long-term virus symptoms could indicate that someone has high levels of inflammation, which can damage the brain by causing stress in brain cells.
The researchers said: ‘Our results confirmed associations of cognitive deficits with mood swings and fatigue, as well as with a variety of other symptoms.
‘Therefore, it is likely that multiple underlying factors contribute to cognitive deficits post-Covid.’
Long Covid is an ill-defined disease that is notoriously difficult to diagnose, with some doctors even saying it doesn’t exist (stock image)
Long Covid is an ill-defined disease that is notoriously difficult to diagnose, with some doctors even saying it doesn’t exist.
Patients with the syndrome complain of a wide range of symptoms, including persistent fatigue, brain fog and the inability to carry on with normal life.
The study – published in the New England Journal of Medicine — calculated a ‘global cognition score’ for participants, which was then used to generate an IQ score.
According to estimates, the average person in the US has an IQ of about 98, with men scoring slightly higher than women.
This suggests that people who say they have Long Covid could have an IQ score of around 93 points – while those who previously had Covid could have an IQ of around 95 points.
An IQ score is a numerical measure of a person’s intelligence, based on a battery of reasoning, problem-solving, memory, and language tests.
But it has limitations, including that it struggles to capture other areas of intelligence, such as creativity and emotional intelligence, and that people who take the test regularly become more familiar with the test, resulting in a higher score.
For the study, scientists sent a request to administer eight cognitive tests to a random group of more than 800,000 people registered with the UK’s National Health Service (NHS).
More than 110,000 people responded, including more than 3,000 people who said their Covid symptoms lasted for more than 12 weeks – which the researchers defined as ‘Long Covid’.
The majority of participants were women in their 50s and 60s and were from a white ethnic background.
Most were also infected, while Omicron was the dominant variant and almost 1,500 people were hospitalized with the virus. A total of 300 participants indicated that they had been admitted to the ICU.
They completed eight tests to measure mental abilities, including memory, spatial working memory and verbal reasoning.
Other results included that participants who reported having early Covid were more likely to experience cognitive decline compared to those in other groups.
Limitations of the study included that there was no data on people’s cognitive abilities before they were infected with Covid, meaning comparisons were not possible.