Misophonia isn't included in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, so there's no set definition for the condition. According to Judith Krauthamer, author of Sound-Rage: A Primer of the Neurobiology and Psychology of a Little Known Anger Disorder , it's "a developmental, neurobiological disorder that is characterized by an emotional rage reaction and a physiological fight/flight reaction to primarily auditory triggers." Tom Dozier, the director of the Misophonia Treatment Institute , defines it as a "Pavlovian conditional physical reflex problem" controlled by the autonomic nervous system. Paul Dion, who runs misophonia.com , puts it more succinctly. "Misophonia is hell," he said.

For a fairly significant percentage of the population, the sound of someone noisily gnawing on chips or wheezing vociferously on the subway car is, quite literally, torturous. Those who suffer from misophonia—also known as selective sound sensitivity disorder or "sound rage"—certain noises are rage- and panic-inducing.

Dozier agreed that misophonia is often misperceived, noting that a lot of the people he's worked with have felt "extreme relief" upon learning that their condition has a name. "[They realize that] they're not crazy; they're not just bitchy," he said. "Misophonia is like physical torture to these individuals, and they've been misdiagnosed over the years and been told, 'It's all in your head.'"

"Misophonia disrupts daily living," she stated. "Someone with misophonia, if someone is chewing, they've got the fight/flight physiological response going on. They're hearing the sound and their thoughts are, Oh, I really hate that person, that person is disgusting. Anxiety level goes up, and [there's] a lot of anger."

Because misophonia is such a newly discovered phenomenon, and because the torment of hell-chewing may seem minor to someone who doesn't understand the neurobiological aspect of the disorder, there are a lot of misperceptions about it in popular culture—on the Today Show, for instance, Kathie Lee and Hoda recently derided the phenomenon as "miso-phony," outraging the misophonia community and resulting in a Change.org petition calling for an apology. In general, Krauthamer said, people often conflate misophonia with simply feeling irritated with annoying sounds, which is incorrect. If someone were chewing gum in a classroom, for instance, any person could feel annoyed by the slurpy mastication; someone with misophonia, however, would have difficulty focusing on the lecture due to feelings of panic or rage.

No one is quite sure what causes misophonia, although researchers believe it has something to do with a neurological misfiring in the limbic system, which rules basic emotions (fear, pleasure, and anger) as well as drives (hunger, sex, and dominance). Some hypothesize that it's similar to synesthesia, a perceptual condition in which one sensory sensation involuntarily triggers another; certain sounds, in other words, will involuntarily trigger the limbic system, which creates an involuntary sensation of anger or fear.

There is a general consensus that misophonia involves an unpleasant physical reaction—skin crawling, jaw or fists clenching, feelings of rage and panic—triggered by some external sound or sight. According to a 2013 study , the most common triggers are eating sounds, like smacking and chewing, and breathing/mouth sounds, like sniffling and wheezing—although other noises, like the oft-maligned nails on a chalkboard, or some visual cues, like the nonstop jiggling of a leg, can have the same adverse effect on some. Most research has found that between 15 and 20 percent of the population has the condition, with women more likely to experience it than men.

For obvious reasons, feeling pure rage in the presence of seemingly innocuous background noise is disruptive one's social life. Krauthamer told me that she feels anxious about going to the ballet, which she loves, because the requisite silence is especially vulnerable to interruption by a sniffler somewhere in the audience. For many people with misophonia, any sort of plan that involves food or drinking is a potential source of anxiety. " Being around with other people is always risky," said Dion. "People can't help making sounds that I am going to be upset with—that's just the way it is."

Read More: Inside the Sensual World of ASMRotica

Things are perhaps even worse within the confines of intimate relationships. If you love someone and want to spend significant amounts of time with them, but find repellent the sounds they make while eating and breathing—both essential functions in keeping a human alive—what is there to do? On misophonia forums and support groups, it's common for users to seethe and share frustrations about the various noises their loved ones unwittingly make; many of them also express guilt about this seething, which, according to experts in the field, they can't control.

"I'm so tired of complaining about this to my boyfriend. He's so supportive and does his best to make my life easier, but I can tell it brings him down when I get all moody," wrote one woman on a private Facebook group for misophonia support. "And I know I'm getting worse. If I even see someone chewing gum in my peripheral vision, my blood gets really hot and I get really stressed... It takes everything in me not to burst into tears immediately, and it's exhausting." (Others, of course, are just pissed off and looking to vent. "My Dad chews everything. I caught him chewing a smooth soup earlier. I walked away," wrote another user, who found immediate support; within an hour, someone else had replied, "I hate this so much. Why chew something that is pre-chewed? Honestly..")

My Dad chews everything. I caught him chewing a smooth soup earlier. I walked away.

Krauthamer is currently writing a book on misophonia and intimacy, for which she has already conducted nearly 100 hours of interviews. "Having this additional veneer, where chewing and snoring and sniffing and chewing nails and slurping and swallowing can put you into an anger state, just adds a whole other layer to problems in relationships," she said. People with misophonia are likely to be hyper-vigilant when it comes to auditory stimuli, involuntarily constantly on the look-out for the sounds they loathe. "If you can't sleep with a person because their snoring triggers you, that's very disruptive. Once the snoring triggers the person, it doesn't matter how loud it is," said Dozier. "If you put in earplugs to drop the volume to where it wouldn't be bothersome to a normal person, you're still being triggered. It's very hard on relationships."

On misophonia support groups, there is copious documentation to support this statement. One post on the misophonia.com support forum, quite tellingly, is titled "I KNEW I could hear my ex blinking!!" In another post, a man from Germany writes at length about his issues with his girlfriend: "My girlfriend breathing, swallowing or chewing makes me furious." And, in March, a woman wrote that she can't sleep in bed with her husband because she hates the sound of his respiration. "I can't justify poking and pushing him just because he is breathing. Instead I find I lay in bed, wide awake, becoming increasingly frustrated and angry," she said. "It isn't unusual for it to make me cry."

It isn't unusual for [my husband's breathing] to make me cry.

For someone with misophonia living with an obstinate and unrelenting soup-chewer or a constant snorer, things may just not work out—though, encouragingly, researchers have proposed several methods of treating misophonia, from apps to exposure therapy to psychosomatic remediation techniques. In the meantime, it seems that the best palliative fix is finding a partner who is understanding and patient. "My husband gets when I get in my misophonia space," said Krauthamer. "If he's eating cereal and I walk into the kitchen to get my coffee, he sees me walk in, and, I swear, his spoon is three inches from his mouth and he holds it there until I walk out. I'm very grateful."