A Vatican-linked university has started teaching classes on Satanism, black magic and exorcism.
The class for clergy and seminarians at Rome's Pontifical Academy "Regina Apostolorum" arose from alarm about what some religious officials see as Satanic practices among young people, especially in Italy.
In one case in Italy in January, members of a heavy metal band called "Beasts of Satan" were ordered to stand trial for their alleged role in three ritual killings. One of the victims was a 19-year-old stabbed to death in 1998. She may have been targeted because her killers believed she was a personification of the Virgin Mary, prosecutors contend.
A major theme of the first day's course was how to differentiate between a person who is possessed and someone who is simply suffering psychological problems.
Rome exorcist Francesco Bamonte described how he works with a team of priests and psychologists to make the distinction before deciding whether to go through with an exorcism.
"If not, I would be inundated with requests from people who don't need me," said Mr Bamonte, who said he performs about 20 exorcisms a year.
The Vatican is also concerned about a growing number of young people who develop what instructors called personal forms of Satanism, outside the sects that are closely monitored by police. They often learn about the devil through the Internet.
"It's a more spontaneous and hidden phenomenon, a problem of loneliness and isolation, a problem of emptiness, that is fulfilled by the values of Satanism," said one of the teachers, Carlo Climati, a specialist on youth culture and Satanism.
He said concerned parents had been asking for a special course for priests.
The pontifical academy is run by the Legionaries of Christ, a conservative order, and teachers for the class include exorcists and psychiatrists.
In 1999, the Vatican issued its first new guidelines since 1614 for driving out devils, offering cautions to exorcists about taking psychiatric problems into account.
The updated exorcism rite, first issued in Latin, was a reflection of Pope John Paul II's efforts to convince the skeptical that the devil is very much in the world. At the time, he gave a series of homilies denouncing the devil as a "cosmic liar and murderer".
Among the signs of possession by the devil, according to church teaching, are speaking in unknown tongues and demonstrating physical force beyond one's natural capacity.