A paracusia, or auditory hallucination,[1] is a form of hallucination that involves perceiving sounds without auditory stimulus. A common form involves hearing one or more talking voices. This may be associated with psychotic disorders such as schizophrenia or mania, and holds special significance in diagnosing these conditions.[2] However, individuals may hear voices without suffering from diagnosable mental illness.[3]
There are three main categories into which the condition can often fall: a person hearing a voice speak one's thoughts, a person hearing one or more voices arguing, or a person hearing a voice narrating his/her own actions.[4] These three categories do not account for all types of auditory hallucinations.
Other types of auditory hallucination include exploding head syndrome and musical ear syndrome. In the latter, people will hear music playing in their mind, usually songs they are familiar with. Reports have also mentioned that it is also possible to get musical hallucinations from listening to music for long periods of time.[5][dead link] This can be caused by: lesions on the brain stem (often resulting from a stroke); also, tumors, encephalitis, or abscesses.[6] Other reasons include hearing loss and epileptic activity.[7]