‘The Afflicted’ by groupwork is on at Summerhall

When I studied Frankenstein at school, we had to learn about the difference between horror and terror.

Horror – a physical experience, an actualised manifestation of emotion that follows a horrifying incident. A sense of revulsion, a sense of sickening disgust.

Terror – a psychological experience, a sense of terrible apprehension that precedes a horrifying incident. A sense of dread, a sense of anxious fear.

Jake Jeppson’s text is inspired by a not-quite-true story, the 2011 case of a group of 24 schoolgirls who became inexplicably prone to vocal and physical tics and twitches. It’s framed around a nameless woman’s true-crime podcast which seeks to get to the source of this incomprehensible phenomenon. Suffice to say, it does not quite go as planned. groupwork theatre’s first production is as startlingly assured, as keen-eyed and razor-sharp as a precocious 17-year-old girl. That might sound like a backhanded compliment. It’s not.

Horror works itself into your body instinctively – if you hear the sound of a chair slamming onto the floor then your body will respond – your breath will constrict, your hands will clench, your eyes will widen. There’s a reason horror fans are sniffy about jump scares. They’re primally satisfying, but they’re a cheap way of guaranteeing a reaction. Provoking a sense of actual, all-encompassing terror – now there’s the rub. Luckily, The Afflicted does that tenfold. We are kept, constantly, on the brink. When the horror-movie inflected beats do come, they almost feel superfluous considering that Summerhall’s Demonstration Room is completely soaked in dread.

Terror is unexplainable. Horror is evident. For me, terror is worse because you can’t see the root of the cause. The thing itself is never as scary the thing that it could be. The Afflicted, like all good Gothic literature, is a fusion of both horror and terror, but it is at its strongest when it leans into the latter. Is it a group of girls seeking attention? Is it satanic possession? Is it repressed trauma? Each is terrible and terrifying in its own way, and we are never granted a definitive coda. Rarely have I been so wonderfully petrified that the action onstage will spill over into the audience, that the chins of the women beside me will start to jut out, that their mouths will open in a silent scream in solidarity with what’s in front of us.

There is more than a touch of Dance Nation to this piece – a similarly feral energy that can never be completely pinned down, can never be completely understood. This is largely down to Vicki Manderson’s gloriously feverish and taut movement sequences, underscored by Lewis den Hertog’s eerily pulsating sound and prickling video design, each disparate element delicately folded into the body of the piece. The four girls tear into dances like nails splitting through skin, ripping through Jeppson’s nervy text like the words can’t possibly hold them any longer. It’s utterly transfixing to watch. It almost feels transgressive to enjoy it so much. The true-crime framing is almost invariably the least interesting part of the show, and fittingly, the narrative becomes increasingly dream-like, increasingly mangled. The further we get, the more enamoured with the girls the production becomes. You watch and you itch to join them. Their bodies vibrate, almost lifting clean off the ground.

Finn den Hertog and Manderson’s co-direction is scalpel-sharp, akin to removing a flap of skin with the edge of a winking silver knife. The hydra-like performers are held at arms-length, each with the same blank, seething stare. You’re never allowed into their heads. I wonder about this retrospectively, having been released from the show’s metallic grip. There’s a long lineage of work about “mass hysteria” (correctly pointed out as an historically gendered term) – Carol Morley’s The Falling, Joan Lindsay’s Picnic at Hanging Rock, and of course, The Crucible – and a few are namechecked early on. But I am still conflicted as to where The Afflicted sits within that family. Where could we go if we climbed into these girls’ heads? If we followed them into the woods? What would happen if we listened to them? What would happen if the scalpel slid deeper?

The Afflicted is on at Summerhall at 7.30pm until 25th August, as part of the Edinburgh fringe. More info and tickets here.