According to a retrospective study published in Lancet Psychiatry, the risk of neurologic and psychiatric symptoms remains elevated in adults up to two years after COVID infection compared to people with other respiratory symptoms.
The research by Paul Harrison, FRCPsych, of the University of Oxford in England, and colleagues identified 1,487,712 patients using data from the US-based TriNetX electronic health records database with a COVID-19 diagnosis from January 2020 to April 2022. Of these patients, 1,284,437 were adequately matched with an equal number of patients with other respiratory infections. Matching was done based on demographic factors, risk factors for COVID-19, severe COVID-19 illness, and vaccination status. Age groups and dates of diagnosis stratified the analysis. Less than 18 years (children)—185,748; 18–64 years (adults)— 856,588; 65 years and older— 242, 101. 57.8% of the sample population were female.
The researchers evaluated the risks of fourteen neurologic and psychiatric diagnoses. They then compared their frequency with the matched cohort (those with a respiratory infection). In addition, they estimated how many people died after a neurological or psychiatric diagnosis during follow-up in each age group. They also compared the matched cohorts of patients diagnosed with COVID-19 directly before and after the emergence of the Alpha, Delta, and Omicron variants.
Following the neurologic and psychiatric diagnosis assessment, the researchers found that cognitive deficit, dementia, psychotic disorders, and epilepsy or seizures were increased at six months in adults 18-64 and remained elevated at the end of the two-year follow-up period. By contrast, the risks of mood and anxiety disorders returned to baseline after one to two months (mood disorders at 43 days, anxiety disorders at 58 days). Subsequently, these risks reached an equal overall incidence to the matched comparison group (mood disorders at 457 days, anxiety disorders at 417 days).
Furthermore, the researchers found that children’s post-COVID-19 risk trajectories were different compared to adults. Children showed an increased risk of cognitive deficit; insomnia; intracranial hemorrhage; ischemic stroke; nerve, nerve root, and plexus disorders; psychotic disorders; and epilepsy or seizures at 6 months. In addition, they discovered that, unlike adults, the cognitive deficit in children had a finite risk horizon (75 days) and a finite time to equal incidence (491 days).
Following the estimation of mortality in each age group, the researchers also found that many older adults who received a neurological or psychiatric diagnosis died, especially those diagnosed with dementia or epilepsy, or seizures.
When the researchers estimated the risk profile following the emergence of the Alpha, Delta, and Omicron variants, they found that the risk profiles were similar just before versus just after the emergence of the Alpha variant. There was an increased risk of neurological and psychiatric outcomes and death rate after the emergence of the delta variant compared with just before. There was a lower death rate for the Omicron variant just before the emergence of the variant, but the risks of neurological and psychiatric outcomes remained similar.
“With Omicron as the dominant variant, although we see much milder symptoms directly after infection, similar rates of neurological and psychiatric diagnoses are observed as with Delta, suggesting that the burden on the healthcare system may continue even with variants that are less severe in other respects,”