New study reveals long-term cognitive and psychiatric effects of COVID-19

The study was conducted by a group of researchers from across the UK, led by the Universities of Oxford and Leicester. The Lancet PsychiatryStudies highlight the persistence and severity of these symptoms, with new symptoms emerging years after COVID-19 first appeared.

The study was conducted among 475 participants (as part of the PHOSP-COVID study) who were asked to complete a series of cognitive tests via computer and to report symptoms of depression, anxiety, fatigue, and subjective perception of memory problems. They were also asked if and why they had changed occupations.

The researchers found that:

• Two to three years after COVID-19 infection, participants' cognitive test scores (tests of attention and memory) were, on average, significantly lower than expected. The average difference was equivalent to 10 IQ points. Furthermore, a significant proportion of people reported severe symptoms, including depression (about 1 in 5), anxiety (1 in 8), fatigue (1 in 4), and subjective memory problems (1 in 4), and these symptoms worsened over time.

• Many people had these symptoms already present 6 months after infection, while others experienced new symptoms 2-3 years after infection that were not present before. New symptoms often appeared in people who were already showing other symptoms 6 months after infection. This suggests that early symptoms can predict later more serious problems and highlights the importance of timely management.

• More than one in four respondents reported changing jobs, with many citing poor health as the reason. Job switching was strongly associated with cognitive impairment, but not with depression or anxiety. This suggests that many people who changed jobs in the months and years following COVID-19 did so because they could no longer meet the cognitive demands of their work, rather than due to a lack of energy, interest, or confidence.

• The degree of recovery six months after COVID-19 infection is a strong predictor of long-term psychiatric and cognitive outcomes, and early intervention to manage symptoms may prevent the development of more complex syndromes and improve overall recovery trajectory.

Dr. Maxim TuckettNIHR Academic Clinical Lecturer Psychiatry “These findings help us understand the burden of brain symptoms people experience years after hospitalization with COVID-19, who is most at risk, and how this affects their ability to work. This is important for policymakers and clinicians and can also help target preventive interventions,” said Oxford University researchers who led the study.

Professor Paul HarrisonJohn E. Kelly, Professor of Psychiatry at the University of Oxford, said: “Understanding the long-term cognitive and psychological impact of hospitalisation with COVID-19 will be important for many, both patients and healthcare professionals. We hope that these findings will stimulate further research into developing effective interventions to help prevent and treat the effects of COVID-19 on the brain.”

Professor Chris BreitlingClinical Professor of Respiratory Medicine University of Leicester“This study reveals important long-term brain-related symptoms after COVID-19 and highlights the urgent need for a better understanding and new treatments for long COVID-19 illness,” the researchers said.

The researchers caution that while this study provides insight into the long-term effects of COVID-19, further research is essential to develop effective interventions. Understanding the biological mechanisms that drive these symptoms and identifying treatment strategies to promote cognitive recovery or prevent further decline are important next steps, the researchers say.

The study sample consisted of individuals who were hospitalized during the first wave of the pandemic (and therefore were not vaccinated at the time of infection) and consented to follow-up assessments (only 20% of those invited), so the findings may not be generalizable to others (e.g., those who did not require hospitalization due to COVID-19).

PHOSP-COVID is a consortium of scientists from across the UK studying the longer-term health of patients hospitalised with COVID-19. The research is funded by MQ Mental Health Research and the Wolfson Foundation, and supported by the National Institute for Health and Care Research (NIHR) Biomedical Research Centre in Leicester and Oxford Health.

Paper 'Trajectories of cognitive and psychiatric symptoms 2-3 years after COVID-19 hospitalization: A longitudinal prospective cohort study'teeth, The Lancet Psychiatry.