Courage comes in all shapes and sizes. Running into a burning building to save a person, exposing corruption in a country whose leadership has a history of making journalists disappear, or confronting a bully are all acts that require conquering one’s fear, even when the potential consequences are life-threatening. But that doesn’t mean that these people don’t feel fear — they actually do just as much as you or I. It’s how they handle the fear that sets them apart.

Oddly enough, though, there are people who literally feel no fear at all. For them, looking death in the eye is no more exciting than an oatmeal breakfast. This rare abnormal condition is either owed to some disease or some brain damage following an accident that affected the brain circuitry associated with the fear response.

No fear, no sense of risk

Take, for instance, the extraordinary case of Jordy Cernik. The British man first knew something was wrong with him when he went skydiving in 2013 and didn’t feel a rush. Since then, Cernik went through all sorts of stunts that would have most people scared beyond belief, including scaling down the edge of the 128-meter National Lift Tower in Northampton, but he found all of them uneventful.

It all started when Cernik was diagnosed with Cushing’s Syndrome in 2005, a medical condition that occurs when the body produces too much cortisol, the main hormone related to the body’s stress response. The excess steroids in the man’s blood made his body feel like it was under a relentless onslaught of imaginary threats. Cernik suffered from excessive weight gain, despite exercising daily and dieting, as well as excessive sweating.

The rare disease, which affects 10 to 15 people per million each year, is caused by a pituitary tumor secreting adrenocorticotropic hormone (ACTH), a hormone that is usually produced by the pituitary gland.

“It’s not a nice one to have,” Cernik told SBS. “Sometimes it can be cured by scraping out the pituitary gland— so that was the brain surgery I had.”

“But mine was persistent and then they ended up having to take my adrenals out just to stop the connection altogether, but then that causes other problems along the way.”

These “other problems” are caused by living life with no fear — quite literally. When Cernik descended one of the tallest towers in the UK on a rope, he was fitted with bands by cognitive scientists that measured his body’s response. These instruments showed that the British man’s body did not react at all as it should have in a normal person.

Scientists believe Cernik’s condition is due to the removal of his adrenal glands during the brain surgery, for which the consequences go beyond just a fearless life. Without any adrenaline in his body, which acts as a sort of painkiller, even a slight injury can be really painful. Also, Cernik isn’t just completely fearless, he’s also devoid of just about any exciting emotion, which makes it incredibly challenging to keep himself motivated.

“It’s just like a switch in my brain that’s gone off and it’s not telling my body to react and it’s a strange feeling,” he says. 

Fear can be your worst enemy, but also your greatest ally

Humans and just about every sentient creature on Earth feel fear for a good reason, playing a crucial role in our survival and, hence, our evolution. Fear is a primordial emotion that is involved in the brain’s “fight or flight” response. It’s the stimulus that keeps us away from predators or emboldens us to fight back when necessary. It’s such an ancient and instinctual emotion, shared with ancestors that lived hundreds of millions of years ago, that it partly explains why humans are still afraid of heights or snakes.

Fear first starts in a part of the brain called the amygdala, which activates other brain areas involved in the fight or flight response and releases stress hormones. In response, the heart and breathing rates rise, blood vessels constrict, and adrenaline kicks in. In some cases, if the fear is overwhelming, the effects on the body can be so extreme that it is actually possible to be scared to death.

Besides the amygdala, another important region of the brain known as the hippocampus is also involved in the fear response. Closely connected to the almond-shaped amygdala, the hippocampus and prefrontal cortex — both heavily involved in higher-order thinking — help us to interpret whether the initially perceived threat is real or not.

For instance, seeing a captive lion at the zoo is much less threatening than seeing the same animal untethered in the African savanna at a leaping distance. The hippocampus provides the explicit memory permitting one to define the context of the fear stimulus while the prefrontal cortex processes and tidies up all this information to establish whether or not you should flee, fight, or just chill since there’s an impenetrable barrier between you and the captive zoo creature.

Most people usually experience it in three stages: freeze (a reaction that is rooted in our evolutionary history to keep us hidden from predators), run (the instinct to move away from danger), and fight (when there’s no way to get away from the fear-triggering object, the ultimate response is to fight).

Fear is automatic, meaning you can’t help feeling it. The degree to which people experience fear and find the power to overcome it, of course, varies among people. But not feeling any fear at all is extremely rare and it goes without saying that it is unnatural.

This woman visited the world’s scariest ‘haunted house’ and was held at knife-point. She never flinched

Clinical observations suggest that humans who’ve suffered amygdala damage have abnormal fear reactions and reduced experience of fear to the point that it is nonexistent. A 2011 study led by researchers at the University of Iowa describes the case of a patient, going by the initials S.M. to preserve her identity, who has focal bilateral amygdala lesions. Her brain damage is the result of a very rare inheritable disease known as Urbach-Wiethe disease, which is characterized by the infiltration of hyaline-like material in the mucous membranes, internal organs, and the brain. In this particular case, calcium deposits on the amygdala caused lesions in the brain region, resulting in an inhibited sense of fear.

The scientists subjected SM to a battery of what were supposed to be nerve-wracking tests, such as exposing her to live snakes and spiders, a haunted house tour, and film clips of scary movies. However, the 44-year-old woman “repeatedly demonstrated an absence of overt fear manifestations and an overall impoverished experience of fear,” according to the researchers.

Although SM told the researchers she ‘hates’ snakes and ‘tries to avoid them’, when she was taken to an exotic pet store, she held one of the snakes for over three minutes during which she rubbed the reptile’s leathery scales, touched its flicking tongue, and closely watched its movements as it slithered through her hands. She also asked 15 different times if she could touch one of the larger snakes, despite the store clerk declining each time, repeatedly cautioning her that the snake in question was dangerous and could bite her.  When asked why she would want to touch something that she knows is dangerous and claims to hate, SM replied that she was overcome with “curiosity.”

During Halloween, the researchers took SM to the Waverly Hills Sanatorium, which regularly ranks as one of the “most haunted” places in the world. The haunted house at the sanatorium is specially designed to elicit fear with eerie scenes, scary music, loud music, and people dressed as monsters, ghosts, or murderers. SM was joined by a group of five women, all of whom were strangers. SM voluntarily led the group through the haunted house, showing no signs of hesitation. “This way guys, follow me!” she beckoned as other members lagged behind her. When monsters leaped out, she always laughed, approached and talked to them. On one occasion, SM frightened one of the supposed monsters by poking them in the head.

The scary movie clips also had the opposite effect. SM exhibited no fear response but she nonetheless found the films exciting and entertaining, inquiring during one particular case about the name of the movie so she could rent it back home. Interestingly, the 10 different fear-inducing films that the researchers selected aimed at inducing a variety of types of emotions, including disgust, anger, sadness, happiness, and surprise. SM exhibited behaviors compatible with all of these emotions — except fear.

Lastly, SM also shared her general experience of fear by completing a self-reported questionnaire and openly talking about events that would have induced trauma in most other people. For instance, had been previously physically accosted by a woman twice her size, was nearly killed in an act of domestic violence, and on more than one occasion she has been explicitly threatened with death. However, on not one occasion did SM act with desperation or urgency.

During one notably impressive feat, SM was walking alone through a small park in her town when a man beckoned her over a bench. As she approached, the stranger pulled her down and struck a knife to her throat, threatening her “I’m going to cut you, bitch!”. Hearing a church choir sing in the distance, she confidently said, “If you’re going to kill me, you’re gonna have to go through my God’s angels first.” The man let her go and SM confidently walked (not ran) away. The next day, she went back to the same park.

“When asked to recollect how she felt during the aforementioned situations, SM denied feeling fear, but did report feeling upset and angry about what had happened,” the researchers wrote.

Similar to SM, then 28-year-old Jody Smith received a complex brain surgery meant to cure his severe epilepsy which resulted in the removal of not only parts of the amygdala, but also the temporal lobe and hippocampus.

“Surgery was the only option to prevent the chance of the seizures getting worse, continuing to damage my brain, or potentially killing me,” he told VICE.

Before his surgery, Smith regularly experienced bouts of panic and anxiety, which he attributed to his past traumatic experiences from both his father and brother dying when he was very young. Two weeks after his operation, however, Smith no longer had panic attacks. He soon found out that he had an almost superhuman ability to be fearless.

According to Smith, however, his fearlessness can be described as nuanced. He claims he still intellectualizes the potential consequences of a threat and is aware of things that could harm him. It’s just that he doesn’t seem to get the fight-or-flight response.

“As an avid hiker, I frequently find myself near cliffs,” he said.

“The experience of fear near cliffs was clearly different. I still didn’t want to fall, and would still feel tense if I started to slip when scrambling, but I didn’t feel the fear part of that. That’s when I started to experiment a bit with my fear: by intentionally walking towards cliffs to see what my instincts would say.”

While out and about in Newark, New Jersey, Smith walked close to a group of men who, by all means, looked like they were about to mug him. But instead of panicking or even experiencing a seizure, as his former self would have, Smith simply and calmly passed through the menacing bunch, much to the men’s surprise who left him alone. “Apparently, my lack of fear struck them,” he said.

What acquired fearlessness may teach us about curing our own anxieties

Although a minimal to non-existent fear response may sound dangerous, we luckily live in a modern society where most of the threats and dangers humans have evolved to face are no longer part of the environment. In fact, one could argue that some of our fearful reactions that could have saved our lives during our caveman days are actually a handicap in today’s society. Such irrational fears fuel anxiety, phobias, obsessive-compulsive disorder, and depression.

Nearly one in four people experience a form of anxiety disorder during their lives, and nearly 8 percent experience post-traumatic stress disorder (PTSD).

But superhuman-like cases such as SM, Smith, and Cernik could help scientists better understand mental health disorders that are due to an exaggerated fear response, such as generalized anxiety disorder.

Frank Herbert’s Dune teaches us that fear is the mind-killer. In the real world, though, fear can also be the life-saver. Like all things in life, a balance must be struck.