Although Covid-19 was first described as a lung disease, as its relentless march continues, we realized it has a far wider reach in the human body.
Covid-19 has been associated with skin rashes, bleeding disorders, and structural damage to the heart and kidneys. It is also involved in brain and mind disorders.
Early studies raised fears that health services would collapse under the shock wave of strokes, inflammation of the brain and muscle disorders. Moreover, reviews of previous coronavirus epidemics have warned that those recovering from Covid-19 could face an increased burden of psychiatric disorders such as depression and PTSD.
But despite research into Covid-19 and the unprecedented and rapid brain production during the pandemic – with hundreds of new articles appearing each week – it was initially difficult to find reliable data to confirm or disprove these fears.
Lots of questions
Thus, a team of physicians, students, and researchers from disciplines including psychiatry, psychology, and neurology joined forces to analyze all available research on the effects of Covid-19 on the brain. In doing so, they intended to cut speculation about the neurological and psychiatric effects of Covid-19. Here’s what they found.
The team realized that many associations between Covid-19 and the brain draw from small, highly selected groups of patients, which risks bias.
To combat this, they knocked down a huge number of potentially relevant papers on neurology and psychiatry Covid-19 (more than 13,000) to 215 that were robust enough for analysis. Collectively, they included 1.05,000 people from 30 countries.
They found that in these studies, the most common neuropsychiatric symptoms were odor loss (anosmia), weakness, fatigue, and taste change (dysgeusia), all of which occur quite frequently.
Anosmia and weakness occurred, for example, in more than 30 percent of patients in the studies they looked at. Therefore, it is very likely that the neuropsychiatric symptoms in Covid-19 are the rule, not the exception.
But encouragingly, initial fears of more serious brain-related conditions – such as widespread inflammation of the brain (encephalitis) and Guillain-Barré syndrome, where the immune system attacks nerves – seem to have been based only on very rare events. Concerns about the huge waves of such conditions seem unfounded.
However, they found that each of the important mental illnesses, such as depression and anxiety, occurs in as many as 25 percent of people with Covid-19.
This can be a big burden for patients in the years to come. Even less frequently reported neurological events, such as stroke (which occurred in about 2 percent of hospitalized patients), will still pose a huge challenge to patients and health systems due to the sheer scale of this pandemic and the fact that they often have life-changing results.
They found that several symptoms (including muscle aches and loss of smell) were actually more commonly reported in those with less severe Covid-19 – contrary to what you might expect. There may be a simple explanation for this: critically ill patients may be less likely to be examined for certain symptoms, especially those that are less severe.
They also saw many disabling symptoms (including fatigue and headaches) present in those who were not in the hospital at all.
The answers are not yet final
Reading this, you may have been struck by the big question about all of these studies: how do we know that Covid-19 actually causes any of these problems? Depression is common – maybe these people developed it without getting Covid-19? And what if you are more likely to catch Covid-19 due to a psychiatric illness? One large study with U.S. data suggests this is the case.
These are all real problems in the data available so far, because if you don’t have a group to compare people without Covid-19, it’s impossible to know if the people you’re studying will have a high rate of neuropsychiatric disorders regardless of coronavirus capture. Ideally, you need a group of people without mental illness as a starting line, and then see what happens when some of them are exposed to Covid-19.
Without such studies, it is difficult to draw any difficult conclusions – and unfortunately, almost all the studies that the researchers looked at did not have comparison groups. However, they are now starting to get some comparative data. For example, we now know that people who have had Covid-19 are more likely to develop mental illness than the general population.
In addition, most psychiatric and neurological problems appear to be more common after Covid-19 than after the flu.
Another issue is that the research to date contains biases that cannot be eliminated. It is biased towards patients in the hospital, when most people with Covid-19 never approach the hospital.
It is biased against acute disease rather than the long-term effects of Covid-19. And he’s biased toward China, the U.S., and other Western countries, with little knowledge of what’s going on in Africa or much of the Pacific region. To get a more comprehensive view, researchers need to conduct future research to have a wider scope.
What we do know is that people with Covid-19 very often have a range of neurological and psychiatric problems, so health care providers must prepare not only for the immediate care of these patients, but also for the intense and often long-term rehabilitation needs that follow.
Early research (yet to be reviewed by other scientists) is being initiated regarding signs of neuropsychiatric symptoms that last for many months after the onset of the disease.
Discovering the true impact of Covid-19 on the brain is only the first step. In reality, the neurological and psychiatric effects of the disease are likely to pose a challenge to clinicians and health systems for many years to come.