March 23, 2022

expert reaction to study looking at cognitive and neuropsychiatric outcomes six months after hospitalisation for COVID-19

A study published in JAMA Psychiatry looks at neuropsychiatric and cognitive outcomes in patients 6 months after COVID-19 requiring hospitalisation, compared with patients hospitalized for non–COVID-19 illness.

Prof Richard Morris, Professor of Neuroscience, University of Edinburgh, said:

“This is an interesting study that asks whether the apparently slow recovery of normal cognition after Covid that required hospitalisation is any different from that seen after other conditions.  The claim is that recovery can indeed be slow but arguably no different from other conditions – implying that there may be nothing special about recovery from COVID.  An alternative perspective recognises that many post-Covid patients recover to normal but a significant minority do not, and an evidence-based stratification was not considered in this study nor was objective brain imaging conducted.  So, in my view this study does not provide robust evidence that the cognitive and neuropsychiatric outcomes after hospitalisation with Covid are less significant than other studies have suggested.”

Dr Max Taquet, NIHR Oxford Health BRC Senior Research Fellow, University of Oxford, said:

“In this study, 85 patients hospitalised with COVID-19 at Copenhagen University Hospital in Denmark were found to have more cognitive problems in the 6 months after hospitalisation than people hospitalised following a severe heart attack or after being admitted to an intensive care unit.  This is an interesting prospective study which confirms earlier findings based on electronic health records data and the PHOSP study.

“Being prospective, the study was able to measure aspects of cognition and to investigate how these change in the first 6 months after hospitalisation.  The causes of such cognitive problems and, importantly, how they can be prevented or treated remain unknown.

“The fact that the study found no evidence for a higher burden of long-term mental health complications after COVID-19 than after severe heart attacks or ICU admission should be interpreted very cautiously.  First, it is well known that heart attacks are associated with a high risk of psychiatric consequences and finding that COVID-19 is associated with a similarly high risk is not particularly reassuring.  Second, because this is a small study, there was a high degree of uncertainty about the risk of psychiatric consequences after COVID-19 compared to severe heart attacks or admission to intensive care.  They calculated the risk to be anywhere from 2 times lower to 2 times higher in COVID-19 compared to the control group.  So this is a case where absence of evidence does not necessarily imply evidence of absence.  Larger prospective studies are thus needed.”

Prof Timothy Griffiths, Professor of Cognitive Neurology, Newcastle University, said:

“I was surprised they found significant cognitive deficits in the COVID group compared to controls at 6 months in this study given that it was not large, and used MoCA.  MoCA is a simple screening instrument designed to identify early dementia that will not pick up more subtle deficits that require more detailed neuropsychological testing.  But as the authors acknowledge the effect on cognition was small.  No psychiatric or neurological deficits were identified.

“The most important finding in the study is the absence of a striking effect of COVID on cognitive, psychiatric or neurological outcome when the patients are compared to a well-matched population of non-COVID patients who also require intensive care.  But I would not rule out an effect based on this study.  Further studies based on such well matched populations with and without COVID are required, that might be larger and use more sophisticated assessments of cognition.”

‘Neuropsychiatric and cognitive outcomes in patients 6 months after COVID-19 requiring hospitalization compared with matched control patients hospitalized for non–COVID-19 illness’ by Vardan Nersesjan et al. was published in JAMA Psychiatry at 15:00 UK time on Wednesday 23 March 2022.

DOI: 10.1001/jamapsychiatry.2022.0284

Declared interests

Prof Richard Morris: “I have no conflicts to declare beyond advising on a separate study, not yet submitted for publication, from another group.  I am not and will not be a co-author.”

Dr Max Taquet: “I have no conflict of interest.”

None others received.