The virus damages the lungs, but the body's response ripples through the entire organism.
In the early months of a global pandemic, British researchers began to understand that the coronavirus was not merely a disease of the lungs but a force capable of reshaping the mind itself. A team at University College London, studying 43 patients, identified five distinct categories of neurological harm — from psychosis and encephalitis to strokes and nerve damage — suggesting that the body's own immune response, not the virus alone, was turning against the brain. This discovery, published in the journal Brain in July 2020, placed COVID-19 within a longer human story of illnesses that remind us how fragile the boundary is between a physical infection and the self we believe ourselves to be.
- A woman who survived COVID-19 returned home only to see lions and monkeys in her house and believe she was being hunted — her recovery had become a different kind of crisis.
- Researchers at University College London found that the virus was triggering strokes in younger patients, autoimmune attacks on nerve tissue, and a rare brain inflammation condition normally seen only in children.
- The immune system, not the virus itself, appears to be the primary agent of neurological destruction — unleashing inflammatory cascades that breach blood vessels and strip the protective coating from nerve fibers.
- Medical teams are racing to alert clinicians worldwide, publishing findings mid-pandemic while the long-term consequences of these brain injuries remain entirely unknown.
When a 55-year-old London woman returned home after recovering from COVID-19, her husband found her obsessively wrapping and unwrapping herself, seeing animals that weren't there, and convinced she was being hunted. Readmitted to hospital, she was treated with antipsychotic medications and improved — but her case raised a question that would drive a dedicated research effort: what was this virus doing to the brain?
A team at University College London studied 43 patients in depth, and their findings, published in the journal Brain in July 2020, revealed five distinct categories of neurological injury: brain inflammation producing delirium and psychosis; inflammatory attacks on the central nervous system; strokes in younger patients under 65; peripheral nerve disorders including Guillain-Barré syndrome, in which the immune system attacks the body's own nerves; and an unclassified group involving spinal cord damage and small brain hemorrhages.
Autoimmune encephalitis was among the most common complications, appearing not because the virus had invaded brain tissue directly, but because the immune system had overreacted. A condition normally seen in children appeared in nearly a quarter of the cases studied. Lead researcher Michael Zandi pointed to low oxygen levels in severely ill patients as one likely factor, while neurologist Jesús Porta described the deeper mechanism: a cytokine storm, in which a flood of inflammatory molecules allows fluid and immune cells to leak into nerve tissue, damaging the myelin that insulates nerve fibers and carries signals between neurons.
As of mid-2020, researchers were still cataloging the immediate damage. What was becoming clear was that COVID-19 was not simply a respiratory illness — it was a systemic disease with the power to alter how the brain and nervous system functioned, in ways that were sometimes reversible, and sometimes not yet understood.
When a 55-year-old woman in London returned home after recovering from COVID-19, her husband noticed something was profoundly wrong. She wrapped and unwrapped herself obsessively. She saw lions and monkeys moving through the house. She was certain someone was hunting her. The doctors who admitted her again recognized the symptoms as psychosis. They treated her with haloperidol and risperidone—antipsychotic medications—and she improved. But the question lingered: what was the coronavirus doing to her mind?
The woman's case was not isolated. In March 2020, a team of British researchers at University College London established a dedicated unit to investigate the neurological complications emerging in COVID-19 patients. They were not trying to count how many people were affected. They wanted to understand what kinds of brain and nerve damage the virus was actually causing. They studied 43 patients in depth.
The findings, published in the journal Brain in early July, revealed that the coronavirus's reach extended far beyond the lungs. The researchers identified five distinct categories of neurological injury. The first included encephalopathies—brain inflammation—that produced delirium and psychosis, like the woman in London experienced. The second involved inflammatory processes attacking the central nervous system directly. The third was cerebrovascular accidents: strokes affecting the blood vessels that feed the brain and lungs. The fourth category encompassed disorders of the peripheral nervous system, including Guillain-Barré syndrome, in which the body's own immune cells attack the nerves themselves. A fifth group remained unclassified—cases involving spinal cord damage, small brain hemorrhages, and elevated pressure inside the skull.
The most common complication was neuroinflamation. Autoimmune encephalitis appeared frequently, triggered not by the virus directly but by the patient's own immune system mounting an excessive response. Among the 43 patients, acute disseminated encephalomyelitis—a condition that typically strikes children and adolescents—showed up in 24 percent of cases. Younger patients, those under 65, suffered strokes. Seven patients developed Guillain-Barré syndrome. The damage was widespread and varied.
Michael Zandi, the lead researcher, told the Spanish newspaper El País that the team was still working to understand the precise mechanisms. The goal of publishing these findings was to alert the medical community and spark further investigation. He pointed to low oxygen levels in the brains of severely ill patients as a likely culprit. But the picture was more complex than simple oxygen deprivation.
Jesús Porta, a neurologist and vice president of the Spanish Society of Neurology, offered another explanation. The virus itself, he suggested, was not directly invading and destroying brain tissue. Instead, the immune system was overreacting—unleashing what researchers call a cytokine storm, a cascade of inflammatory molecules that allows fluid and immune cells to leak from blood vessels into nerve tissue. The coronavirus damages the lungs, but the body's response to that damage ripples through the entire organism. Myelin, the protective coating that insulates nerve fibers and allows electrical signals to travel smoothly between neurons, can be damaged in this process. The infection in one organ becomes a crisis in another.
As of mid-2020, the long-term consequences remained unknown. Researchers were still cataloging the immediate effects. The cases they documented—hallucinations, strokes, autoimmune attacks on the nervous system—suggested that COVID-19 was not simply a respiratory illness. It was a systemic disease with the power to reshape how the brain and nervous system functioned, sometimes in ways that antipsychotic medications could reverse, and sometimes in ways that remained to be understood.
Notable Quotes
We are still working on what causes the brain and nerve diseases in these patients. The goal of this study was to describe the syndromes in detail to alert people and drive more research.— Michael Zandi, lead researcher at University College London
It is not the virus that directly affects the central nervous system, but rather an exaggerated response of the immune system.— Jesús Porta, neurologist and vice president of the Spanish Society of Neurology
The Hearth Conversation Another angle on the story
Why would a respiratory virus cause someone to see animals that aren't there?
The virus itself probably isn't invading the brain directly. What's happening is the immune system is overreacting—flooding the brain with inflammatory molecules that damage the protective coating around nerve cells. It's like the body's defense system is so aggressive it starts harming its own tissue.
So the psychosis isn't the virus. It's the cure.
Not exactly the cure, but the immune response. The virus triggers it, but the damage comes from the body fighting back too hard. That's why some patients improved with antipsychotic drugs—those medications can help calm the inflammation.
The researchers studied 43 patients. That's not many.
No, it's not. But what matters is they found five distinct categories of brain damage. Strokes, autoimmune attacks on nerves, inflammation of the spinal cord. The variety itself was the discovery—this wasn't one thing happening to one type of patient.
Did they know why some patients got these complications and others didn't?
Not yet. That's what they were calling for more research on. Low oxygen levels seemed to play a role, but there were clearly other factors at work.
A woman saw lions in her house. That's terrifying.
It is. And it happened after she'd already recovered from the respiratory infection. She was home, she thought she was safe, and then her own immune system was still attacking her brain.