In Brief: The Quirky Brain: Why people hear voices
Auditory hallucinations occur in about 60% to 80% of patients with schizophrenia. These voices tend to be unfriendly or hostile, offering unwelcome commentary about the patient or a situation. Less often, the voices may command the patient to do something.
Patients with schizophrenia say the voices they hear sound different from those of friends or family members, and are distinct from unspoken thoughts or an attempt to imagine someone else speaking. Some researchers suggest that the experience of an auditory hallucination is similar to the voices that even healthy people sometimes hear either when falling asleep or waking up.
Imaging studies have consistently shown that Broca's area, the part of the brain involved in generating speech, is activated when a person is experiencing an auditory hallucination. What is less clear is why this occurs.