You are in a crowd when you hear your name. You turn, looking for the speaker. No one meets your gaze. It dawns on you that the voice you heard must have sprung from your own mind.
This foray into the uncanny is as close as most people come to experiencing auditory hallucinations or "hearing voices," a condition that affects 70% of patients with schizophrenia and 15% of patients with mood disorders such as mania or depression. For these individuals, instead of hearing just one's name, voices produce a stream of speech, often vulgar or derogatory ("You are a fat whore," "Go to hell") or a running commentary on one's most private thoughts.
The compelling aura of reality about these experiences often produces distress and disrupts thought and behavior. The sound of the voice is sometimes that of a family member or someone from one's past, or is like that of no known person but has distinct and immediately recognizable features (say, a deep, growling voice). Often certain actual external sounds, such as fans or running water, become transformed into perceived speech.
One patient described the recurrence of voices as akin to being "in a constant state of mental rape." In the worst cases, voices command the listener to undertake destructive acts such as suicide or assault. But hearing voices is not necessarily a sign of mental illness, so understanding the mechanics of auditory hallucinations is crucial to understanding schizophrenia and related disorders.