"It's short and it's very easy to implement," said Tom Craig, a professor of social psychiatry at King's College London's Institute of Psychiatry, whom Leff has trained to provide the therapy.
Those in the control group were offered the treatment at the end. After the therapy, patients were evaluated by a psychiatrist with commonly used rating scales for psychotic symptoms, their beliefs about the voices, and depression.
Avatar therapy's overall effect was at least twice that of the only other non-pharmaceutical treatment for schizophrenia, cognitive behavioral therapy, Leff said. The approach probably worked for the disabling mental illness because the avatar and its voice were the patient's creation and the image of the persecuting voice validated their experience, according to Leff.
"One patient after two sessions said the voice was gone," Leff said. "He'd been hearing this voice for 3 1/2 years all the time. It woke him up at 5 a.m. and went all day long. He said, ''It's as if she left the room.'"
Another patient had been a successful property developer until he began hearing the voice of the devil 16 years earlier, took its advice and lost all his money, Leff said. The voice ceased as the patient was walking away from the hospital after his second session of treatment.
"He came back to see me on the third session and said 'he's gone, he's stopped talking to me'," Leff said. "He said 'thank you for giving me my life back.'"
The treatment didn't initially affect symptoms of depression in the patients, though in follow-up evaluations three months later they reported their depression symptoms had significantly improved, according to the study. Thoughts of killing themselves also declined, important in patients who face a 10 percent risk of suicide, Leff said.