People who have or have had COVID-19 tend to report more complaints about their cognitive abilities, according to new research published in Psychiatry Research. But these complaints do not appear to reflect actual deficits in cognitive performance.
“The topic of COVID-19 and, somewhat later, long COVID, has interested scientists from a wide range of disciplines worldwide,” explained study authors Steffen Moritz and Anna Baumeister, who are affiliated with the Clinical Neuropsychology Unit at the University Medical Center Hamburg-Eppendorf.
“Especially with long COVID, reports of neurocognitive impairments accumulated, which naturally arouse particular interest for us as neuropsychologists. Various psychiatric complaints (e.g., depression) have been exacerbated by the psychological stress of the coronavirus pandemic in general population and may also have a negative impact on neurocognitive abilities. Therefore, we wanted to take a closer look at the neurocognitive complaints associated with Long COVID as well as their objective correlates.”
In 2015, the researchers conducted a study with 877 healthy, middle-aged individuals that assessed depressive symptoms, subjective cognitive complaints, and objective cognitive performance. For their current study, they collected follow-up data from 428 participants in 2021.
Participants who reported a current or previous SARS-CoV-2 infection in 2021 tended to report more subjective complaints about their attention (e.g. “I have trouble concentrating”), compared to those who had not been infected. However, “their objective test performance does not reflect a reduction in selective attention,” the researchers found.
Those who had been infected with COVID-19 also exhibited lower objective memory performance and higher depressive symptoms in 2021 compared to their non-infected counterparts. But these differences “were nullified when patients’ pre-existing levels are taken into account,” said the study authors.
“It is important for us to emphasize that we do not dispute the existence of long COVID or that self-reported patient complaints are negligible or even delusional,” Moritz and Baumeister told PsyPost. “On the contrary, subjective neurocognitive complaints do not always have to correspond to objective performance; we know this from other disorders (e.g., depression).”
“Thus, this does not mean that there is no underlying problem in these self-reported complaints, however, the nature may be more psychological than thought previously. Therefore, we would like to call above all for a good differential diagnosis by physicians and therapists. Also, increased self-awareness (e.g., due to clustered media reports) of symptoms of illness, which probably each of us experienced during the coronavirus pandemic, can exacerbate such symptoms. This knowledge may already take some burden off ‘the average person.'”
Surprisingly, only about 4% of the sample reported a current or previous SARS-CoV-2 infection, which may have influenced the results.
“We were particularly surprised by how few of the total of over 400 participants reported a SARS-CoV-2 infection,” Moritz and Baumeister said. “Although the survey took place at a relatively early stage of the pandemic in Germany, we would have expected more people to have contracted the disease. This may be due to a simple bias that healthy individuals or those less affected are more likely to participate in a survey. Otherwise, the results were generally consistent with our hypotheses.”
“The stated point above is also a major limitation. Also, we only have data collected online. These are less reliable than studies accompanied by medical professionals. Because of this and with such a small subgroup, we cannot draw reliable conclusions, but the results still give an indication. More such studies are needed to paint a clearer picture of long COVID.”
“But this is exactly the problem: in very few cases there are comparative data of patients from before the pandemic,” Moritz and Baumeister added. “This poses a major methodological problem, as no clear causal conclusions can be drawn. For this reason, despite the limitations mentioned above, we are proud of our study and the results.”
The study, “Long-COVID or long before? Neurocognitive deficits in people with COVID-19“, was authored by Anna Baumeister, Anja S. Göritz, Charles Benoy, Lena Jelinek, and Steffen Moritz.