One in three Covid-19 survivors receive a neurological or psychiatric diagnosis within six months of infection, a study has found.
University of Oxford research, published yesterday in The Lancet Psychiatry, looked at the health records of 236,379 US Covid patients – and compared them with 105,579 patients diagnosed with influenza and 236,038 with any respiratory tract infection.
It found 34% of people with Covid-19 were diagnosed with a neurological or mental health disorder within half a year of being infected. This incidence was higher than following other respiratory infections studied, even after considering other risk factors such as age and sex.
For 13% of the people diagnosed, it was the first neurological or psychiatric diagnosis they had ever received – and the more severely ill with Covid the patient has been, the more the risk of developing a condition was found to increase.
Study co-author Dr Max Taquet 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.’
Overall, there was a 44% greater risk of neurological and mental health disorders after Covid-19 than after flu, and a 16% greater risk than after respiratory tract infections.
The most common diagnoses were anxiety disorders (in 17% of patients), mood disorders (14%), substance misuse disorders (7%) and insomnia (5%).
Neurological disorders were less likely, including 0.6% for brain haemorrhage, 2.1% for ischaemic stroke and 0.7% for dementia.
A neurological or psychiatric diagnosis occurred in 39% of those who were admitted to hospital, 46% of those in intensive care, and 62% in those who had encephalopathy – described as ‘delirium and other altered mental states’ – during their Covid-19 infection.
The authors argued that ‘urgent’ research was needed to understand how and why such disorders are more likely to develop, given the ‘substantial effects on health and social care systems likely to occur’.
The Alzheimer’s Society head of research Dr Sara Imarisio agreed that ‘it is important that researchers get to the bottom of what underlies these findings’.
She explained: ‘While this study analysed data from the first six months following a Covid-19 diagnosis, this increased risk may not be limited to this time frame.
‘Given that the peak of Covid-19 hospitalisations in the UK occurred in January this year, and we already expect a backlog of people waiting to come forward or be seen about memory concerns, services must be prepared to deal with a large number of potential dementia cases.’
She added: ‘While Covid-19 has already had a disproportionate effect on people with dementia in many ways, these neurological impacts are an additional concern and must be a focus of future research efforts into the long-term impact of the virus.’