What is arachnophobia?

Arachnophobia is a fear of arachnids — a group of arthropods that includes spiders, scorpions, ticks and mites. From the Greek word arachne, meaning spider, and phobos, meaning fear, arachnophobia can be a debilitating condition for some. 

More than 10 million people in the United States suffer from some kind of phobia, the American Psychological Association reported, and 40% of these phobias are related to creepy-crawly critters like insects, snakes and, of course, spiders. 

Related: What really scares people: Top 10 phobias

Why are people afraid of spiders?

So why have some people developed such a deep-seated fear of spiders and their eight-legged friends? 

"We know many species of spiders are poisonous and bite, and we know this from direct experience, science, biology, TV and seeing other people get bitten," Dr. Alan Manavitz, a clinical psychiatrist at Lenox Hill Hospital in New York City told Psycom, a mental health website. "Therefore, when we see a spider near us, a natural response is to feel fear and avoid the spider."

One theory suggests that nurture instead of nature may be to blame. (The 1990 film Arachnophobia certainly didn't put arachnophobes at ease.) The condition is likely to be more prevalent in the United States than in Cambodia, for instance, where tarantulas and scorpions are considered a delicacy, The Washington Post reported. 

Another theory suggests that our fear of the creepy-crawly arachnids may have helped us stay alive long ago. But although most spiders have venom, few actually have fangs large enough to pierce our skin. Of the 35,000 spider species in the world, only a dozen of them pose a risk to humans. Evolutionary psychologists have suggested that our early ancestors may not have been able to tell which spiders' bite would have rendered harm, leading them to develop a fear of all spiders. And some research supports this hypothesis. 

Related: An Australian man screamed so loud at a spider that the cops showed up

For example, when a team of scientists at the Max Planck Institute for Human Cognitive and Brain Sciences in Germany showed a group of babies images of spiders, flowers, fish and snakes, the infants' pupils dilated the most when they were shown images of the spiders and snakes. The researchers said this suggests people inherently develop fears of such creatures, Live Science previously reported. 

A 2016 study published in the journal Biological Psychology found that arachnophobes also overestimate the size of the spiders they come into contact with. "This study revealed how perception of even a basic feature such as size is influenced by emotion, and demonstrates how each of us experiences the world in a unique and different way," Tali Leibovich, study author and scientist at Ben Gurion University of the Negev in New York City said in a statement. 

Related: The greater the fear, the larger the spider

So what exactly is it about spiders that inspires such a negative reaction? It all comes down to the "disgust emotion," according to Psychology Today. Several research articles have shown that there isn't really one thing about spiders that triggers the disgust emotion. Some blame a tarantula's hairiness, some point to their venom and others blame their skittish movement. All of which suggests that instead of fear, what people may be feeling is disgust. 

An arachnophobe's response to seeing a spider is often visceral. Phobias can induce a number of physical reactions, including nausea, accelerated heart rate and dilated pupils. Other reactions to the sight of these animals include wrinkling of the nose (thought to help prevent foul smells and pathogens from entering) and frowning, which could have helped toxic liquids drip from the lips of our ancient ancestors. 

Can arachnophobia be cured?

Researchers have relied on many methods to help patients conquer their fear of spiders. 

Exposure therapy is often lauded as the most successful treatment of the condition. In exposure therapy, patients with the phobia are exposed to the thing they fear — in this case, spiders — in a safe and controlled setting. The thought is that patients can rewire their brain, and create a "new safe memory that resides in [their] brain alongside the bad memory," opinion columnist Richard A. Friedman wrote for The New York Times.

Related: New Rx for spider fears? Shout it out

In 2014, scientists reported that a man was cured of his arachnophobia after doctors removed a chunk of his brain. According to the case study, published Oct. 5, 2014, in the journal Neurocase, doctors scooped a piece of tissue out from the left side of the man's amygdala, to alleviate seizures caused by sarcoidosis. After the procedure, his fear of spiders turned to fascination. 

A 2016 study in the journal Biological Psychiatry reported that patients once fearful of spiders were able to touch a tarantula within days of taking the drug propranolol while also being exposed to a tarantula for two minutes at a time. At the end of three months, the patients held the tarantula. After a year, the study reported, their fear subsided entirely. 

Related: Spider phobia cured with 2-hour therapy

For some, the movie "Spiderman" has helped diminish the paralyzing effects of arachnophobia. In 2019, a study published in the journal Frontiers in Psychiatry reported that watching clips from either Spider Man or Ant Man helped people alleviate symptoms of the condition. The team of scientists asked participants to take a survey about their fear before and after watching a clip from Marvel's Spider Man. Participants reported fewer symptoms after watching just a seven second clip from the movie. 

Technology has become increasingly vital as a treatment for arachnophobia. As virtual reality has become more and more popular, scientists are exploring ways to dampen and even cure the effects of arachnophobia by tapping into the virtual world. 

Additional resources

• Learn more about phobias, in general, from the U.S. National Library of Medicine.
• Read more about specific phobias and how common they are from the National Institute of Mental Health.
• Find helpful resources for supporting mental health and treating mental health disorders at MentalHealth.gov.