Jessie (name disguised) lost eye contact with me and, cracking a smile, spoke to the invisible third party in the room. "I heard you," he replied to thin air, giving a dismissive wave of his hand.

Auditory hallucinations, including hearing voices, are one of the hallmarks of schizophrenia, as up to 80 percent of people diagnosed with schizophrenia report hearing voices. Auditory hallucinations ...