TEENAGERS HAD mass hysteria, fainted in the aisles and regurgitated their popcorn. Back in 1973, cinemas across Britain literally shook at the first screenings of a movie justifiably called “the most frightening ever made”.

Now the 25-year ban on video release of The Exorcist has been lifted, and youngsters well below 18 will sneak a chance to watch it after their homework - in friends’ homes, or their own.

This will revive fears that the portrayal of demonic possession of a young girl could cause emotional trauma. But if the jury will be out for a while yet on the video’s effect on today’s teenagers, new insights from the past decade might lead adults to a radical re-interpretation of The Exorcist - which links with very topical issues of child abuse.

William Peter Blatty’s book was based on a real case. Nowadays, children are increasingly receiving psychiatric diagnoses: look at the popularity of attention deficit hyperactivity disorder. Would a “shrink” decide today that instead of being possessed by a vile hissing demon this child actually suffered from dissociative identity disorder - the dull new name for multiple personality disorder?

For leaving aside the garish special effects and throwing up, Regan displayed classic symptoms of the most traumatised victims of occult groups. Was the model for The Exorcist really the victim not of grunting consummation by evil spirits but of sadistic child abuse by nasty humans?

That’s no Trivial Pursuit question to today’s child protection professionals, and to teachers who work with the emotionally disturbed in special schools or secure units. They don’t meet kids who levitate and vomit as their heads spin through 180 degrees. But they do sometimes work with children who say and do very frightening, bizarre and sexually perverse things; who go into trance-like states and behave like someone else; who believe they are hopelessly evil and irredeemable.

This is traumatic, isolating work. Staff deserve information and support in struggling to understand what on earth could have happened to the young people they care about. But after the ridicule in high-profile cases like Rochdale and Orkney perverse sadistic child abuse by a small minority of occult weirdos isn’t supposed to exist.

What is dissociation? A mild form takes place when we realise we have just driven 20 miles of motorway while our minds are elsewhere. Many people who face torture learn to “distance” their minds when pain is unbearable, so they feel they are looking down at their own bodies.

The mind may fragment into several so-called “personalities”, which have in fact been invented by the brain itself. Some protect and defend the self by taking the pain, others mock the self with its tormentors’ voices - spitting like demons, or simply cursing like abusive Uncle Joe. It would seem incredible, were it not well-documented in trauma literature from many countries.

Only now are psychologists appreciating the human mind’s extraordinary ability to find ways of surviving horrors from earliest childhood. Later, though, the price is often mental anguish, amnesia and confusion. When the disturbed children in residential or secure units become adults, they are often labelled, hospitalised, even “sectioned” as paranoid schizophrenics. Their post-traumatic symptoms are mistaken for diseased brains.

It’s an intriguing question: might we just learn something new about the extremes of child abuse by looking at The Exorcist in a new way? I doubt it. If demonic possession is bad news, extreme child abuse by respectable citizens is 10 times worse. Look how many years it took the victims of the Edinburgh children’s homes scandal to find someone who believed them.

It’s a certainty more than half the atheist and agnostic viewers of The Exorcist video, schoolchildren and adults alike, will emerge teeth chatteringly convinced demonic possession can happen, and resolved to ensure their bedside light is always on. Yet try to tell them about weird forms of child exploitation by mere mortals, whose only “paranormal powers” are the result of conjuring tricks. Then, we are told, it’s all far too incredible and unbelievable: no-one could possible swallow that.

Sarah Nelson is a specialist writer and researcher on child sexual abuse.