Exorcisms are a booming industry in the UK, partly driven by immigrant communities and Pentecostal churches, according to a report from a Christian thinktank.

However, the vast majority of people being exorcised have mental health problems that require psychiatric assistance, says the report, published on Wednesday by Theos.

The report calls for an analysis of “the burgeoning exorcism scene in the UK in the light of concerns over how it is being used and its possible negative consequences”.

It says the “astonishing increase in demand” has arisen “in defiance of any actual rules or procedures put in place by any church”. In 2012, the Church of England reissued guidelines on “good practice in the deliverance ministry”.

The Theos report – Christianity and mental health: theology, activities, potential (pdf) – does not reject the possibility of demonic possession. It says: “Certainly there is a biblical warrant for the dangers of demonic forces, and Jesus’ great commission to the disciples includes the explicit command to ‘cast out demons’. However, there is also need for serious caution.”

One danger was “Christian over-spiritualising” – a “tendency to ascribe anything and everything to spiritual causes when other medical ones may exist”. Another was a possible overlap between “demonic possession” and mental health issues.

One chaplain who described themselves as a “Bible-believing evangelical” told Ben Ryan, the report’s author, that “in all their experience with a mental health trust they had ‘never seen anything I would say that looked like demonic possession, but I’ve seen plenty of people who have been told that’s what they’re experiencing by other Christians’.”

The report says: “One of the frustrations of medical professionals with Christians comes from accounts and anecdotes of people with medical health issues going off their medication because they’ve been told that prayer is enough, and relapsing as a result.

“This is a classic example of well-meaning initiative with the potential for serious harm. It runs the risk of becoming a sort of spiritual abuse – which can be understood as psychological abuse inflicted upon the victim by members of their own religious group.”

Ryan told the Guardian that exorcism was “the serious end of a larger wedge. Some Christians are sometimes treating mental health issues as if everything is spiritual. So if someone tells a church leader they are suffering from depression, sometimes the response is that everything can be treated with prayer. The extreme end of that is exorcism.”

He said some charismatic and Pentecostal churches, particularly in areas with large west African communities, were advertising “healings” and exorcism outside their premises.

“If the church tells people that the problem is the demon inside you, and they perform an exorcism, but you don’t get better – and in fact you might get worse, believing you’ve failed to overcome the demon – that’s a form of spiritual abuse.”

A C of E spokesperson said: “Our guidelines state that particular caution needs to be exercised, especially when ministering to someone who is in a distressed or disturbed state.”