A new study examining health data from 18 million people found that unvaccinated people had higher rates of mental illness for up to a year after developing severe COVID-19. Vaccination appears to reduce the negative impact of COVID-19 on mental illness. A University of Bristol-led study published in JAMA Psychiatry on August 21, 2024, investigated the association between COVID-19 and mental illness depending on time since diagnosis and vaccination status.
COVID-19 has been shown to be associated with psychiatric disorders in both hospital and population studies, but to date there is limited evidence of an association between psychiatric disorders and individuals receiving the COVID-19 vaccine.
A multi-institutional team, including researchers from the University of Bristol Medical School, University College London (UCL), the Universities of Oxford, Cambridge and Swansea Medical School, sought to answer this question by analysing the medical records of 18,648,606 adults aged 18 to 110 years registered with general practitioners in England.
Of the 18,648,606 adults in the cohort studied in the period before vaccination became available, the mean age was 49 years, 50.2% (9,363,710) were women, and 1,012,335 adults had a confirmed COVID-19 diagnosis (recorded in laboratory data, general practitioner, hospital or death register).
The authors also studied a cohort that included 14,035,286 vaccinated adults, of whom 866,469 had confirmed COVID-19, mean age 53 years, and 52.1% (7,308,556) were women, and a cohort that included 3,242,215 unvaccinated adults, of whom 149,745 had confirmed COVID-19, mean age 35 years, and 42.1% (1,363,401) were women.
The researchers used these data to compare the incidence of mental illness in people in each cohort before and after they were diagnosed with COVID-19. Mental illnesses included in the study included depression, serious mental illness, generalized anxiety disorder, post-traumatic stress disorder, eating disorders, addictions, self-harm, and suicide.
The team found that the incidence of most of these symptoms was higher 1 to 4 weeks after a COVID-19 diagnosis than before or without COVID-19 symptoms. Elevated rates of psychiatric disorders were primarily seen after severe COVID-19 leading to hospitalization and remained elevated in unvaccinated individuals for up to a year after severe COVID-19.
Increased rates of mental illness were primarily seen after severe COVID-19 leading to hospitalization, but not after COVID-19 that did not lead to hospitalization. For example, the incidence of depression after COVID-19 without hospitalization was up to 1.22 times higher than before or without COVID-19, whereas the incidence of depression after COVID-19 with hospitalization was up to 16.3 times higher than before or without COVID-19. In the vaccinated cohort, the incidence of depression after COVID-19 without hospitalization was similar to that before or without COVID-19.
The findings add to a growing body of evidence highlighting the high risk of developing psychiatric disorders after a COVID-19 diagnosis and the benefit of vaccination in reducing this risk, with stronger associations with COVID-19 severity and primarily longer-term associations with new-onset psychiatric disorders.
“Because severe mental illness is associated with more intensive medical needs and long-term health and other adverse outcomes, our findings have important implications for public health and mental health service delivery.”
Dr Venecia Walker, lead study author and Senior Research Fellow at the University of Bristol
Dr Walker added: “Our findings highlight the importance of COVID-19 vaccination for the general population, and particularly for people with mental illness, who may be at higher risk of both SARS-CoV-2 infection and adverse outcomes after COVID-19.”
Jonathan Stern, professor of medical statistics and epidemiology at the University's Bristol Medical School (PHS), director of the NIHR Bristol Biomedical Research Centre and one of the study's authors, added: “We have already identified links between COVID-19 and cardiovascular disease, diabetes and now psychiatric disorders. We continue to investigate the impact of COVID-19 through ongoing projects looking at links between renal, autoimmune and neurodegenerative diseases and COVID-19.”
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Journal References:
Walker, VM, et al. (2024) COVID-19 and mental illness in vaccinated and unvaccinated individuals. JAMA Psychiatry. doi.org/10.1001/jamapsychiatry.2024.2339
