August 17, 2022

expert reaction to study on risk of neurological and psychiatric conditions up to two years after COVID-19 infection

A study published in The Lancet Psychiatry looks at neurological and psychiatric risk trajectories after SARS-CoV-2 infection.

This Roundup accompanied an SMC Briefing.

Prof David Menon, Head of the Division of Anaesthesia, University of Cambridge, said:

“The findings here are keeping with our paper from earlier this year (https://doi.org/10.1016/j.eclinm.2022.101417)  in hospitalised patients with Covid-19, which showed

1. Discordance between the cognitive deficits and mental health outcomes – with the former being related to acute illness severity
2. Minimal effect of time on cognitive deficits within a horizon of up to 10 months
3. The impact of hospitalised disease being equal (in magnitude) to ~20 years of ageing (between 50 y and 70 y)
4. A deficit pattern that was distinct from both normal ageing and Alzheimer’s disease

“As regards to mechanisms – the most likely impact is likely to be that of a maladaptive host response – both innate immunity and adaptive immunity (autoantibody responses) – which may cause ongoing neurological insult, as evidenced by persistently elevated protein biomarkers of brain injury (particularly Tau).”

Prof Paul Garner, Emeritus Professor in Evidence Synthesis in Global Health, Liverpool School of Tropical Medicine, said:

“The Covid-19 pandemic has caused stress in our society-not just by the virus making people ill, but disruption to daily living and fear of what a new virus can do to us. This article reassures us that mood and anxiety problems appear to return to normal levels quite quickly. The research also confirms that common post-viral problems such as brain fog can persist for some months. I think we need to be careful in the interpretation of the reported small increases in dementia and psychosis: these are, in my opinion, more likely to be related to the societal upheaval and dystopia we have been living through rather than being a direct effect of the virus.”

Dr Rachel Sumner, Senior Research Fellow, Cardiff Metropolitan University, said:

“This is an extremely robust and well conducted study, using data from a large sample, and across multiple nations. The collection of data from different nations helps to minimise some of the effects that we may see from pandemic safeguard legislation, such as the implementations of lockdowns, which have been rallied against by some for their potential to harm mental health. The findings are alarming and are critically important in our current context of unmitigated Covid spread. The finding of complex and potentially severe psychiatric and neurological fallout of Covid infection adds yet more weight and concern to the impact of repeated infections that will occur should the virus continue to be allowed to spread to re-infect with little to no control.

“The evidence from the study is particularly worrisome given that there has been little observed effect of variant, meaning that even though some variants may have been deemed “milder” in their impact on people during infection, the longer-term consequences of infection appear to be similar regardless of variant. This is even more concerning for those that work in frontline roles, who are exposed to Covid infection repeatedly with very little ability to keep themselves safe from it.

“This study adds another layer of potential future harm for health services across the world, adding to other evidence that has emerged on cardiovascular disease risk also. Long term effects of Covid will cause longer term economic harm in the form of extensive health service utilisation and employment absenteeism or even unemployment, which is a risk for some that are most effected by the conditions highlighted in the study. It is also of concern that patients that experience Covid and go on to develop some of these disorders will continue to have delay in diagnosis and treatment with healthcare systems that are struggling to deal with both Covid infections and backlogs of patient waiting lists.

“Other studies have noted repeatedly that Covid results in the development of “microclots” in the blood, which have been associated with other health outcomes such as cardiovascular disease. There is also evidence that Covid is able to disrupt some of the regulatory processes that support our neurons, the cells in our brains and nervous systems responsible for transmitting the huge amount of information back and forth required for us to think, feel, and move. How much of these outcomes are associated with the potential for Covid to create changes in our blood, such as with micro clots, which can disrupt blood flow to critical systems, and how much may be associated with these neural regulatory processes is difficult to say. There is still much about Covid that we do not fully understand despite the very excellent work that has been done in this area.”

‘Neurological and psychiatric risk trajectories after SARS-CoV-2 infection: an analysis of 2-year retrospective cohort studies including 1 284 437 patients’ by Maxime Taquet et al. was published in The Lancet Psychiatry at 23:30 UK time on Wednesday 17^th August.

DOI: http://dx.doi.org/10.1016/S2215-0366(22)00260-7

Declared interests

Prof David Menon is an author on the paper cited in his comment.

Prof Paul Garner: “None.”

Dr Rachel Sumner: “No interest to report.”