Search for apeirophobia on Google and you’ll find hundreds, if not thousands, of message-board posts and comments similar to this on popular Internet forums like Reddit, Quora, and Yahoo! Answers. Websites dedicated to phobia help and support, such as Phobia Fear Release and MedHelp, all have comment threads on apeirophobia, too. On these sites, Apeirophobes share experiences and swap advice. Even though most describe dealing with unrelenting anxiety, many seem comforted by knowing they aren’t alone.

Despite all this discussion, there is so little research on apeirophobia that it lacks its own Wikipedia entry. It is not explicitly recognized by the Diagnostic and Statistical Manual of Mental Disorders, the American Psychiatric Association’s standard reference for psychiatry, but it does meet their criteria for a “specific phobia,” which is classified as an anxiety disorder. It is included on many sites with informal phobia lists, but it is absent from the websites of the Mayo Clinic and the National Institute of Mental Health, as well as WebMD. A Google Scholar search doesn’t yield a single quantitative study on the phobia.

Grasping for some sense of its prevalence, I posted on Facebook, asking if anyone had experience with apeirophobia. I received considerably more responses than expected. One friend said that he used to get so overwhelmed during sermons in early adolescence that he felt physically sick. Another wrote, “The thought of eternity still fills me with anxiety when I wake up from naps. My solution: I stopped napping.”

Where does this fear come from? A realization that an eternal afterlife could become infinitely repetitive? The recognition that one lacks control over their own destiny?

Martin Wiener, a former colleague of mine at George Mason University who researches the neural underpinnings of time perception, notes that the brain region hypothesized to control long-term planning, the frontal lobe, is one of the last to develop in humans as they grow. “In adolescence, there is a dawning realization that occurs where one realizes they will become an adult,” Wiener says. “I suspect that, in apeirophobia, one comes to the ‘realization’ that after death you will live forever (if you believe this), and in simulating that experience in your mind, one realizes that there is no way to project ahead to ‘forever’—and that experience is, inherently, anxiety-provoking. As such, the anxiety that these folks are feeling may not be much different than the fear of growing up, getting old, or death.”

Maybe human brains, as finite instruments with limited cognitive and computational capacities, are flat-out not hardwired to have a conception of something completely absent from sensory experience. Evolution has done just fine without organisms that contemplate infinity, after all. Doing so wouldn’t have likely offered any survival advantages to pre-modern humans.