The coronavirus may trigger the onset of psychiatric disorders in some survivors, research suggests.
It is increasingly coming to light that not every patient who goes on to test negative for the infection returns to a clean bill of health. So-called “long COVID” has been shown to cause everything from fatigue and palpitations to rashes and even signs of organ damage.
Feeling the virus’ mental health effects were less well understood, scientists from the University of Oxford combed through medical data on more than 69 million people across the US.
Among patients with no psychiatric history, testing positive for the coronavirus more than doubled their risk of later developing anxiety, insomnia or even dementia compared with the participants who overcame flu.
Although unclear exactly why this may be occurring, previous research has suggested the coronavirus could trigger an immune response that leads to inflammation in the brain.
Early in the outbreak, experts also warned the pandemic could have a “profound” and “pervasive” impact on people’s mental health for some time to come.
To better understand the coronavirus’ potential psychiatric effects, the Oxford scientists analysed more than 69 million people from 54 healthcare organisations.
Of the participants, over 62,000 tested positive for the coronavirus between 20 January and 1 August.
Results – published in the Lancet Psychiatry – suggest that among the patients with no psychiatric history, catching the coronavirus was linked to more than double the risk of receiving such a diagnosis 14 to 90 days after testing positive, compared to those who overcame flu.
The coronavirus was also found to raise the risk of a psychiatric diagnosis – namely anxiety, fatigue or dementia – by 70% compared to surviving another respiratory infection.
The coronavirus survivors were also more likely to receive a psychiatric diagnosis than the participants who endured a skin infection, broken bone, or gall or kidney stones.
Overall, just under one in five (18.1%) of the coronavirus patients received a psychiatric diagnosis in the 14 to 90 days after testing positive for the infection, of which 5.8% were first-time diagnoses.
Among those over 65, 1.6% received a dementia diagnosis specifically for the first time between 14 and 90 days after swabbing positive for the coronavirus.
Being diagnosed with a psychiatric disorder in the past year was associated with a 65% higher risk of catching the coronavirus in the first place.
This remained true after the scientists adjusted for physical risk factors that are known to trigger coronavirus complications, like obesity and diabetes.
The team added, however, they “cannot exclude possible residual confounding by socioeconomic factors”.
Watch: Can you catch coronavirus twice?
The scientists concluded: “Survivors of COVID-19 appear to be at increased risk of psychiatric sequelae and a psychiatric diagnosis might be an independent risk factor for COVID-19.
“Although preliminary, our findings have implications for clinical services and prospective studies are warranted.”
Writing in a linked Lancet Comment, Dr Robert Yolken from John Hopkins University pointed out a psychiatric diagnosis may just represent the first time it is picked up by a medic, rather than the disorder specifically being triggered by the coronavirus.
Professor David Curtis from University College London (UCL) agreed, adding: “These psychiatric diagnoses get made quite commonly when people present to doctors and it may be unsurprising this happens a bit more often in people with COVID-19.
“[These patients] may understandably have been worried they might become seriously unwell and will also have had to endure a period of isolation.
“It is [also] well known psychiatric illness is associated with increased risk of many other physical health issues and also that COVID-19 infection risk is associated with socioeconomic factors which may be more prevalent in people with mental illness.”
This is not the first time experts have warned the coronavirus could affect the brain.
In July, a small study by UCL found a “higher than expected number of people” with the coronavirus showed signs of brain damage, with these patients not necessarily having severe respiratory symptoms.
“Whether we will see an epidemic on a large scale of brain damage linked to the pandemic – perhaps similar to the encephalitis lethargica [sleeping sickness] outbreak in the 1920s and 1930s after the 1918 influenza pandemic – remains to be seen,” said study author Dr Michael Zandi.
The 1918 pandemic left some patients with viral encephalitis, brain swelling that can occur if a pathogen enters the central nervous system.
Some survivors went on to develop viral Parkinsonism, defined as symptoms similar to Parkinson’s disease like shaking and stiff movements.
Speaking of the research, Professor Anthony David from UCL said: “Post-infection neurological syndromes comprise a chapter found in all textbooks of neurology and this topic has been boosted by the recent description of novel autoimmune encephalitides [brain inflammation]”, he said.
“COVID-19 can now be added to the list of possible causes.
“Will that chapter remain a relatively slim esoteric one? In my opinion, probably yes, as I think these complex neuropsychiatric conditions associated with COVID-19 are likely to be rare.”
Professor David pointed out people who survived Spanish flu but went on to develop sleeping sickness specifically were not found to have traces of the virus in their brain, suggesting the complication was “immune mediated”.
“Again, despite the scrutiny on the current pandemic and the near instantaneous speed of information sharing in the internet age we have yet to hear of the first case of post COVID-19 encephalitis lethargica and so it seems unlikely these neurological complications will be common symptoms but time will tell,” he added.
Another UCL study published in May suggested coronavirus survivors may endure delirium and post-traumatic stress disorder.
Speaking of the Oxford research, Dr Michael Bloomfield from UCL said: “This well-conducted study adds to a growing body of evidence that COVID increases the risk of a range of psychiatric illnesses, including post-traumatic stress disorder.
“This is likely due to a combination of the psychological stressors associated with this particular pandemic and the physical effects of the illness, although further work is needed to understand this fully.”
Watch: What is long COVID?