A higher incidence of mental illnesses persists for up to a year following severe Covid-19 in unvaccinated people, according to a new study involving UCL researchers.
The study, looking at health data from 18 million people and published in JAMA Psychiatry, investigated associations of Covid-19 with mental illnesses according to time since diagnosis and vaccination status. It found that vaccination appeared to mitigate the adverse effects of Covid-19 on mental illness.
Covid-19 is associated with mental illnesses in both hospital and population-based studies. However, until now, there was limited evidence about the association of Covid-19 with mental illnesses when individuals had received Covid-19 vaccination.
A cross-institution team, including researchers from UCL, the University of Bristol Medical School, University of Oxford, University of Cambridge and Swansea University Medical School, sought to answer this by analysing the medical records of 18,648,606 adults aged between 18 and 110 years and registered with a GP in England.
Using these data, the researchers compared the incidence of mental illnesses in people before and after a Covid-19 diagnosis, in each cohort. Mental illnesses included in this study comprised depression, serious mental illness, general anxiety, post-traumatic stress disorder, eating disorders, addiction, self-harm, and suicide.
The team found that the incidence of most of these conditions was higher one to four weeks after Covid-19 diagnosis, compared to the incidence before or without Covid-19. This elevation in the incidence of mental illnesses was mainly seen after severe Covid-19 that led to hospitalisation and remained higher for up to a year following severe Covid-19 in unvaccinated people.
For instance, the incidence of depression after non-hospitalised Covid-19 was up to 1.22 times higher than that before or without Covid-19, while the incidence of depression after hospitalised Covid-19 was up to 16.3 times higher than that before or without Covid-19.
In the vaccinated cohort, the incidence of depression after non-hospitalised Covid-19 was similar to that before or without Covid-19.
The findings add to a growing body of evidence highlighting the higher risk of mental illnesses following Covid-19 diagnosis, and the benefits of vaccination in mitigating this risk, with stronger associations found in relation to more severe Covid-19 disease, and longer-term associations relating mainly to new-onset mental illnesses.
One of the study's lead authors, Professor Praveetha Patalay of the MRC Unit for Lifelong Health & Ageing at UCL, said: "Our mental health research programme since the start of the Covid-19 pandemic has highlighted the higher adverse impacts of pandemic measures on people with prior mental health difficulties, and the substantial mental health consequences of both infection control measures and infection itself.
"Taken together, the evidence further highlights the pressing need for better efforts to prevent and treat mental ill-health."
Dr Venexia Walker, one of the study's lead authors from the University of Bristol, said: "Our findings have important implications for public health and mental health service provision, as serious mental illnesses are associated with more intensive healthcare needs and longer-term health and other adverse effects.
"Our results highlight the importance Covid-19 vaccination in the general population and particularly among those with mental illnesses, who may be at higher risk of both SARS-CoV-2 infection and adverse outcomes following Covid-19."
Co-author Professor Jonathan Sterne, also from the University of Bristol, said: "We have already identified associations of Covid-19 with cardiovascular disease, diabetes and now mental illnesses. We are continuing to explore the consequences of Covid-19 with ongoing projects looking at associations of Covid-19 with renal, autoimmune and neurodegenerative conditions."
This work was supported by the Covid-19 Longitudinal Health and Wellbeing National Core Study, which is co-led by Professor Nishi Chaturvedi (MRC Unit for Lifelong Health & Ageing) and funded by the Medical Research Council (MRC) and National Institute for Health and Care Research (NIHR).
The study aims to understand the health, social and economic impacts of the Covid-19 pandemic by uniting established population cohorts and national anonymised electronic health records.
