William Friedkin directed the 1973 movie The Exorcist. It became one of the highest-grossing films in history, was a major pop culture influence, and was labeled by critics and voters as one of the scariest movies of all time. But in a recent issue of Vanity Fair, Friedkin admitted that he had never witnessed an actual exorcism. So Friedkin, who considers himself an agnostic, traveled to Italy and watched a real exorcism. When he returned to the U.S. he showed the video to two of the world's leading neurosurgeons and researchers in California and to a group of prominent psychiatrists in New York.

After watching the video, Dr. Neil Martin, chief of neurosurgery at the UCLA Medical Center, said:

There's a major force at work within her somehow. I don't know the underlying origin of it … This doesn't seem to be hallucinations … It doesn't look like schizophrenia or epilepsy … I've done thousands of surgeries, on brain tumors, traumatic brain injuries, [etc.] … and I haven't seen this kind of consequence from any of those disorders. This goes beyond anything I've ever experienced—that's for certain.

Dr. Itzhak Fried, a neurosurgeon and clinical specialist in epilepsy surgery, seizure disorder, and (December 20156

It looks like something authentic. She is like a caged animal. I don't think there's a loss of consciousness or contact … I believe everything originates in the brain. So which part of the brain could serve this type of behavior? … [But] can I characterize it? Maybe. Can I treat it? No.

Friedkin was surprised by the neurosurgeons' response:

They wouldn't come out and say, "Of course this woman is possessed by Satan," but they seemed baffled as to how to define her ailment … I went to these doctors to try to get a rational, scientific explanation for what I had experienced. I thought they'd say, 'This is some sort of psychosomatic disorder having nothing to do with possession.' That's not what I came away with. Forty-five years after I directed The Exorcist, there's more acceptance of the possibility of possession than there was when I made the film.