Over the past 10 years in the United States, the number of official priest exorcists has more than quadrupled from 12 to 50.

For many of these priests, such as Father Gary Thomas who trained in Rome, it is an ongoing struggle to keep up with the demand.

Father Thomas, along with Father Vincent Lampert, discuessed with The Telegraph how the increase in drug and pornography addiction, failure of the mental healthcare system and a rise in popularity of “pagan activities”, such as using a Ouija board to summon the dead, are among the factors contributing to the huge increase in demand for exorcisms.

An expanding spiritual void in the lives of Americans, and the diminishing authority of the Church, are to blame as well, they stated.

In the US, over the last decade, television shows depicting reported paranormal events and possession as well as books and films about exorcism and the supernatural have proliferated in the cultural mainstream. This has also aided in the popularity increase.

“We’re gaining all sorts of knowledge,” he says, “but there’s still that emptiness within us that is being filled with addictive behaviour such as drugs and pornography.

Father Thomas tries to answer all exorcism inquiries that come to him. “Often the stories are very complicated and many (seeking help) have been suffering for a long time” he says. He describes his correspondents as “desperate” people who have had no positive results from going down the path of psychology and psychiatry.

“They’re sick in one way or another,” he explains. “And sometimes they do have a demonic problem. These are the local ones (in my parish).”

Medical doctors, clinical psychologists, and psychiatrists are part of Father Thomas’s discernment team. Team members must be Catholic and they must believe in the existence of Satan. He also has a prayer team present with him at every exorcism or deliverance.

The Vatican held a new training course for priests in exorcism this year, due to the claims that demands for deliverance from demonic possession have greatly increased across the the world. The Vatican-backed International Association of Exorcists, which represents more than 200 Catholic, Anglican and Orthodox priests, said the increase represented a “pastoral emergency”.

According to a priest from Sicily, the number of people in Italy claiming to be possessed had tripled to 500,000 a year, and an Irish priest has said demand for exorcisms has “risen exponentially”.

In the past, exorcists’ names were kept secret to protect priests from frivolous requests; today contact details can be found on the internet. But there is still no central database for the number of exorcisms performed.