A WaPo article about an exorcist

The vast majority of people who are referred to him suffer from mental illness, he said. He refers most of them to local psychiatrists and mental health professionals.

But the Devil does exist, he said, and his emissaries occupy the bodies of people from time to time. Possession is never involuntary. You have to actually court the Devil, to actively seek his dark magic, before he can invade the flesh. Faith is required, if not in God, then certainly in the Devil, he said.

“Most of the time it is people who are angry with God,” he said. “They broke up with a boyfriend, or someone close to them dies, or they didn’t get a job that they really needed. They become angry. They turn on God and seek evil. It’s not like a cold or the flu. You can’t just catch it.”

At 74, Elizaga is an iconic and a curious figure in Montevideo. He has traveled to Brazil, Lebanon and other countries studying exorcisms and cults. He writes books on exorcisms. His parish is immensely popular. The police said they have asked his help in solving difficult cases. In 1986, Pope John Paul II named him a consultant to the Vatican on non-Christian cults.