Does the sound of eating, a pen clicking or finger tapping grate on your nerves? We dig into the unusual phenomenon of why some people are enraged by everyday sounds.

Picture this: the person sitting across from you at a communal table is enjoying their meal – really enjoying it by the sound of it. You try to ignore it but you can’t stop your eyes zeroing in on their mouth. Every smack and slurp makes your stomach roil and you can feel your hackles rise. “Don’t they know how annoying they’re being?” you fume internally. Sound familiar?

An extremely odd response

Misophonia, a.k.a. selective sound sensitivity syndrome, is described as the unusually intense, negative emotional experience to specific, normally harmless sounds experienced by some people.

People who experience misophonia – ‘misophonics’ –  are commonly triggered by other people’s breathing noises, lip smacking during eating, drinking, pen clicking, tapping and typing. Some people can also be triggered by rhythmic visual stimuli, for example legs swinging or watching someone chew. Note that misophonia is different to what people feel in response to almost universally-discomforting sounds, such as fingernails scraping on a blackboard or screaming.

Self-reports of misophonia are quite common (about 1 in 5) but in reality, less than 1 in 10 people experience responses intense enough to cause significant disturbance to their everyday lives. It greatly affects their ability to concentrate on tasks as well as engage in normal social interactions such that they may even withdraw from society. When surveyed, misophonics typically say these experiences started in childhood or adolescence.

Misophonics respond to trigger sounds with a range of negative emotions including disgust but the most common response is anger. Over time, the stress they feel can further induce anxiety and panic and they avoid situations where they may be exposed to triggers. During an episode, sufferers experience physical symptoms that indicate arousal of the sympathetic nervous system, which is the one responsible for our ‘fight-or-fight’ responses. They experience muscle tension and increased heart rate, blood pressure and body temperature.

Short-term coping strategies vary from trying to block out the sound (e.g. with headphones), being physically aggressive with the offender, confronting them to stop, to even mimicking the offender to reduce their irritation. The last one is interesting because misophonics don’t have the same negative responses when they themselves make the sounds that usually trigger them.

Not just imagining things

It was only in the early 2000s that misophonia was given a name and considered worthy of scientific research. But its physiological effects on individuals are very much real, as researchers have found using the skin conductance response test to measure sweating: an indicator of the activation of the fight-or-flight nervous system.

So why do misophonics react the way they do?

We know abnormal hearing isn’t the cause of their woes. Misophonics have normal hearing thresholds and respond to typical unpleasant sounds with the same annoyance that other people do. Misophonics aren’t more angry than other people until they’ve been exposed to their trigger. Instead, brain imaging studies suggest that it’s the unusual way their brains learn to associate emotions with hearing trigger sounds.

A breakthrough study by British researchers in 2018 found that a brain region called the anterior insular cortex (AIC) functions differently in misophonics. The AIC integrates information from both inside and outside the body as well as processes emotion. It is connected to the ‘salience network’, a group of areas in the frontal lobe of the brain, which also help process and regulate our emotions, for example by picking out what’s worth responding to.

In misophonics, trigger sounds increase brain activity in both the AIC and salience network whereas in other people, increased activity is seen in AIC but the salience network’s activity is decreased. The structure of the frontal lobe is also different in sufferers.

Back tracking even further in the brain processing stages, later research argues that misophonics have an exaggerated activation of the flight-or-fight system to unpleasant sounds in general. This may make them pay more attention than normal to potentially-triggering sounds.

Mind over matter? Towards treatment

Unfortunately, we don’t yet have any effective treatment for misophonics. A big part of the problem is that misophonia still isn’t recognised as an official disorder. There isn’t even a list of diagnostic criteria that is universally agreed upon by researchers. Another complication is that people with misophonia often also have other conditions such as obsessive-compulsive disorder and Tourette syndrome.

Despite this, case studies show that psychological treatments can work for misophonia, in particular cognitive behavioural therapy. Patients are trained to focus on neutral sounds and do mindfulness/relaxation exercises. Treating misophonia with drugs is another but little-explored option.

So, in the meanwhile, don’t hold your breath – or breathe too loudly!

Links and stuff

• Misophonia, or Why I hate the Sound of Chewing Salad
• Misophonia: Why do some sounds drive people crazy?
• Self assessments to see if you might have misophonia
• Video: What It’s Like To Hate the Sound of People Eating