A group of patients older than 10 and who became infected with the SARS-CoV-2 virus after Jan. 20, 2020, and were still alive Dec. 13, 2020, was compared with a group of 105,579 patients diagnosed with influenza and a group of 236,038 patients diagnosed with any respiratory tract infection (including influenza).
The team estimated 34% of the COVID-19 group were diagnosed with a neurological or mental health disorder after infection. For 13% of these people, it was their first recorded neurological or psychiatric diagnosis.
The most common diagnoses after COVID-19 were anxiety disorders (in 17% of patients), mood disorders (14%), substance misuse disorders (7%) and insomnia (5%). The incidence of neurological outcomes was lower, including 0.6% for brain haemorrhage, 2.1% for ischaemic stroke and 0.7% for dementia.
Compared with the other two groups, and taking into account age, sex, ethnicity and existing health conditions, there was overall a 44% greater risk of neurological and mental health diagnoses after COVID-19 than after flu, and a 16% greater risk than after respiratory tract infections.
“Our results indicate that brain diseases and psychiatric disorders are more common after COVID-19 than after flu or other respiratory infections, even when patients are matched for other risk factors,” Oxford’s Dr. Max Taquet, a co-author of the study, said. “We now need to see what happens beyond six months. The study cannot reveal the mechanisms involved, but does point to the need for urgent research to identify these, with a view to preventing or treating them.”
The study was published Tuesday in the Lancet.