Misophonia is characterized by a negative reaction to a sound with a specific pattern and meaning to a given individual.
Individuals with misophonia are sensitive to a specific set of trigger sounds, which are usually recognized since childhood; these sounds tend to be trivial noises produced by other people, including gum popping, food chewing or crunching, nose sniffing, breathing, pen clicking, clock ticking, whistling, lip smacking, and finger or foot tapping. However, it is important to note that trigger sounds do not necessarily need to be produced by other people: the noise produced by a train or an airplane, distant sounds of engines, as well as sounds made by animals can all potentially result in misophonic reactions in selected individuals.
Source: Neuropsychiatr Dis Treat. 2015; 11: 2117–2123
The condition was first described in 2000, and not yet been formally classified as a psychiatric or auditory condition.
The cause of misophonia is currently unknown, but is hypothesised to be a brain disorder rather than an ear disorder.