A sneak peek for Sunday's episode of Keeping Up With the Kardashians hints that Kendall Jenner may be struggling with anxiety. (“Everyone says I’m fine, but I don’t feel fine,” she tells her mom, Kris, in the clip.) It's not clear what's going on with the 20-year-old model, but the mysterious teaser made us wonder if it has anything to do with the phobia Kendall recently mentioned on her app.

In August, Kendall revealed her struggle with Trypophobia, a fear triggered by clusters of holes. "Trypophobics are afraid of tiny little holes that are in weird patterns. Things that could set me off are pancakes, honeycomb or lotus heads (the worst!)," she wrote. “I can’t even look at little holes—it gives me the worst anxiety. Who knows what’s in there???”

Though trypophobia is not yet recognized as a medical diagnosis, the term has been circulating on the Internet since 2009. And the first research on the strange fear was published in Psychological Science in 2013. The authors of that study concluded that the phobia might actually be an evolutionary adaptation, since images that induce trypohobia share visual characteristics with a range of poisonous organisms (like snakes and spiders). While trypohobics aren't conscious of why they recoil from clustered holes, they may be experiencing a "rapid nonsconscious response," the authors write.

But Health's contributing psychology editor Gail Saltz, MD, points out that a true phobia is quite severe. She describes it as "an irrational fear that is intense enough to cause symptoms of pain, and causes the person to avoid the feared thing."

Feeling revolted by certain types of images isn't necessarily a phobia as it's defined by the Diagnostic and Statistical Manual of Mental Disorders, she saysSome people are disgusted by small holes because it reminds them of insects, or something that has been eaten by worms, Dr. Saltz adds. 

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Phobias are often treated with exposure therapy, whereby a person is gradually exposed to the thing they're afraid of until they become desensitized to it. Though this treatment is really meant for irrational fears, Dr. Saltz says. “If you are just disgusted by something, that may not change."

It remains to be seen whether it’s trypophobia that’s keeping Kendall up at night, or something else. We'll have to tune in on Sunday (9 p.m. ET on E!) to find out.