The estimated incidence of a neurological or psychiatric diagnosis in the following six months was 33.6 per cent, with 12.8 per cent of the patients receiving their first such diagnosis. Estimated incidence among patients admitted to an ITU was 46.4 per cent, with 25.8 per cent of cases being a first diagnosis.
The Covid-19 cases were also compared with a cohort of patients diagnosed with influenza, and another diagnosed with any respiratory tract infection including influenza in the same period. Covid-19 patients were found to be 16 per cent more likely to develop a psychological or neurological disorder than after other respiratory infections, and 44 per cent more likely than people recovering from influenza.
Mood, anxiety or psychotic disorders affected 24 per cent of all patients with Covid-19 but was higher in those admitted to hospital (25 per cent) and ITUs (28 per cent), and even higher in those who experienced delirium while ill (36 per cent).
Professor Sir Simon Wessely, Regius Chair of Psychiatry, King’s College London, commented on the findings: "This is a very important paper. It confirms beyond any reasonable doubt that COVID-19 affects both brain and mind in equal measure. Some were already known – for example increased rates of stroke and also anxiety disorders. Others less so – dementia and psychosis for example.
"What is very new is the comparisons with all respiratory viruses or influenza, which suggests that these increases are specifically related to COVID-19, and not a general impact of viral infection."
Dr Musa Sami, Clinical Associate Professor in Psychiatry, University of Nottingham, said: "What we do not fully understand at the moment is the mechanism by which COVID-19 has this effect: psychological stress, longer stays in hospital and characteristics of the illness itself may play a part."
The Oxford researchers conclude that complementary study designs, including prospective cohorts, are needed to corroborate and explain these findings.
Link: 6-month neurological and psychiatric outcomes in 236 379 survivors of COVID-19: a retrospective cohort study using electronic health records