The forces of unreason are on the march in Federica Di Giacomo’s disturbing documentary. It is about two priests in Sicily specialising in exorcism, as part of a new upswing in exorcism in Catholic churches across Europe and the US. They arrive to conduct special masses and one-to-one sessions. One even performs exorcisms over the phone.

There is a subsidiary pleasure to be had in guessing which people featured here have seen William Friedkin’s film The Exorcist. (I very much suspect that one woman, who goes into the creepy-throaty Satan voice, falls into this category.) But basically it’s a melancholy study of people who clearly suffer from depression, drug abuse, anxiety and compulsive disorders, herded into a situation that creates group hysteria and group dysfunction – and behaviour that would otherwise only be expected in some improv drama class.

There’s a bizarre moment when a priest fails to catch someone who is rocking backwards: the sufferer falls back on top of someone else on the floor supposedly in a trance of deliverance – and this person jumps up, affronted. The priests look like harassed GPs making their rounds. Very different from Max von Sydow’s gaunt suffering.