One in three people who were severely ill with coronavirus were subsequently diagnosed with a neurological or psychiatric condition within six months of infection, a study has found.
The observational research, which is the largest of its kind, used electronic health records of 236,379 patients mostly from the US and found 34% experienced mental health and neurological conditions afterwards. The most common being anxiety, with 17% of people developing this.
Experts warned that healthcare systems need to be resourced to deal with patients affected by this, which could be “substantial” given the scale of the pandemic. They anticipate that the impact could be felt on health services for many years.
Neurological diagnoses such as stroke and dementia were rarer, but not uncommon in those who had been seriously ill during infection. Of those who had been admitted to intensive care, 7% had a stroke and almost 2% were diagnosed with dementia.
The study, which was published in the Lancet Psychiatry, found that these diagnoses were more common in Covid-19 patients than among those who had the flu or respiratory tract infections over the same time period.
After taking into account underlying health characteristics, such as age, sex, ethnicity and existing health conditions, there was a 44% greater risk of neurological and mental health diagnoses after Covid-19 than after flu.
Prof Paul Harrison, lead author of the study, from the University of Oxford, said: “These are real-world data from a large number of patients. They confirm the high rates of psychiatric diagnoses after Covid-19 and show that serious disorders affecting the nervous system (such as stroke and dementia) occur too. While the latter is much rarer, they are significant, especially in those who had severe Covid-19.
“Although the individual risks for most disorders are small, the effect across the whole population may be substantial for health and social care systems due to the scale of the pandemic and that many of these conditions are chronic. As a result, health care systems need to be resourced to deal with the anticipated need, both within primary and secondary care services.”
There has been growing concern that coronavirus survivors might be at increased risk of neurological disorders. A previous observational study by the same research group reported that people are at increased risk of mood and anxiety disorders in the first three months after infection.
However, until now, there have been no large-scale data examining the risks of neurological as well as psychiatric diagnoses in the six months after infection.
The most common diagnoses after Covid were anxiety disorders (occurring 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 a brain haemorrhage and 0.7% for dementia.
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 authors note several limitations to their study including the fact many people with symptoms of the virus do not present for health care, so the people studied here are likely to have been more severely affected than most. It was noted that the severity of the neurological and psychiatric disorders is not known.
Dr Jonathan Rogers, who was not involved in the study, from University College London, said: “[This] study points us towards the future, both in its methods and implications … Sadly, many of the disorders identified in this study tend to be chronic or recurrent, so we can anticipate that the impact of Covid-19 could be with us for many years.”