Francis Merson, clinical psychologist and founder of the Paris Psychology Centre, told Bored Panda that fear of heights, or acrophobia, is quite common, affecting around 5% of the population, with women slightly more likely to be acrophobic than men.

“As is often the case with phobias, fear of heights taps into an ancient fear response, which has evolved to help keep us safe from a basic existential threat—falling from a great height. Our human or pre-human ancestors who had no fear of heights would have been more likely to expose themselves to danger, while those afraid of heights were more likely to survive and pass on their genetic material to us,” the clinical psychologist explained. This means that a fear of heights is something most of us have inherited as part of our genetic hardware.

”If you’re wondering how come some people, especially repair workers, bridge painters, and skyscraper window cleaners, seem to have little if any fear of heights, Francis has an explanation. “As a general rule, any kind of fear reduces with repeated exposure. So the more time you spend at high altitude without anything bad happening, the less it's going to freak you out. In psychological terms, you desensitize to the feared stimulus (in this case, heights)—which means that you gradually begin to perceive it as something safe.”

Francis added that he wouldn't be surprised if people who choose to work at high altitudes are the ones who score pretty low on acrophobia to begin with.

The question remains when fear of heights becomes a problem. Francis argues that feeling a bit queasy when looking down from a great height, like the top of the Grand Canyon, is normal—and not a sign that there is anything wrong with you.

Meanwhile, “people with severe acrophobia can be unable to stand on a chair without panicking, let alone go to a rooftop party! Fear of heights becomes a problem when it is extreme, causing distress and interfering with your life. In this case we might start to talk about a specific phobia, which is an intense, incapacitating fear of one particular thing, such as heights, spiders or bodies of water. In the case of acrophobia, this generally leads to avoidance of anything above the ground floor—elevators, multi-story malls, office buildings, flying, hiking, etc.”

The clinical psychologist explained that specific phobias such as acrophobia generally respond well to treatment. “The gold-standard method is graduated exposure, which involves confronting your fear gradually, step-by-step. So you might start by looking down out of a one-story window, and when you feel comfortable at that level, moving to a second-story window, then the third-story, and so on,” Francis explained.

“The important thing is to make sure you feel relaxed and comfortable at each progressive stage. Patients find they're soon able to feel OK at heights they never imagined they could handle!” he concluded.