The feeling of fear is an intrinsic element of human existence, serving as a protective mechanism that alerts us to danger and facilitates survival. But what if a person lacked the capacity to experience fear? This is the reality for a handful of individuals due to rare medical conditions.
Jordie Sarnik, from the UK, was diagnosed with Cushing’s syndrome in 2005, a disorder that leads to an overproduction of the stress hormone cortisol. Treatment involved the removal of his adrenal glands, and while the procedure was successful, it resulted in the complete absence of fear. Sarnik’s experiences included riding rollercoasters, skydiving, and rappelling, all without any fear response. His heart rate remained normal, showing no signs of anxiety or panic.
Another case involves an American woman, S.M., who is afflicted with Urbach-Wiethe disease, a rare genetic condition, also known as lipoid proteinosis. This disorder damages the amygdala, the region of the brain responsible for fear processing. Scientists conducted several experiments on S.M., exposing her to frightening films, haunted houses, snakes, and spiders. She showed no sign of fear; instead, she was often drawn to the objects or situations typically associated with fear.
S.M.’s behavior patterns are notably unusual. She tends to approach people closely, irrespective of whether they are strangers. During one experiment, she was asked how close she felt comfortable being to someone, and she replied with a mere 0.34 meters (approximately a foot), a considerably shorter distance than the average person. This fact underlines that fear plays a role in shaping social behavior.
There were instances when S.M. was threatened at knifepoint or gunpoint, but she did not feel threatened. This lack of fear sometimes led her into difficult situations.
Scientists say that fear functions in two ways: first, in response to external threats like an animal attack, and second, due to internal threats, such as suffocation. The amygdala is essential for identifying external threats, whereas internal anxieties, such as distress caused by carbon dioxide buildup, are regulated by the brainstem.
In an experiment, S.M. was exposed to carbon dioxide, and she experienced intense panic and fear for the first time, highlighting that fear isn’t entirely dependent on the amygdala.
According to scientist Feinstein, a creature without an amygdala could perish swiftly in the wild as it cannot recognize threats. However, S.M. has been alive for over 50 years without an amygdala. These cases demonstrate how fear protects us and affects our social and emotional behavior.