In the eerie Council Chamber of Battersea Arts Centre, a partition has been raised between the two halves of the room. With half the audience on one side and half on the other, two different plays are on show. In what feels like a set botched together from bits and pieces, the audience wait to find out which of tonight’s two performances they will see. Into the space walk the four actors; one sits down in front of us and the other three pass through the small opening to the other half of the audience. Although we can hear what is going on on the other side, their actions can only be left to the imagination.

The Eradication of Schizophrenia in Western Lapland falls somewhere in the realms of what can only be considered the extreme of experimental theatre. An exploration of the nature of psychosis, this incredibly powerful, thought provoking and deeply uncomfortable play is unlike anything I have seen before. On one side of the dividing wall we find scenes from a mother’s kitchen, and on the other, the discussions held in a therapist’s office. Inspired by the open dialogue method which has almost eradicated schizophrenia in Finland, the play probes the uncertainty and confusion of the audience to highlight the different perceptions of madness and the importance of family in tackling mental illness.

Performed by the Ridiculusmus Company, known for their work which bridges both the serious and funny, this play is branded as a black comedy. Would I call it that? Absolutely not; but it says something about this company that when faced with such a challenging subject matter, a need for humour is not a side thought but a necessity.

The performances in both halves of the room start simultaneously. Although separated in time and space, the small passage through the partition allows for a transition of actors from one performance to the other. However, in changing performance, the characters themselves don’t change. The result is an audience overwhelmed by barrages of conflicting information about each of the characters.

What appears to be the archetypal relationship between therapist and patient twists and turns, leaving the audience questioning themselves and their perceptions as much as the characters on show. Added to overheard fragments from across the partition, the line between reality and delusion becomes increasingly blurred. Moments of egomania and subtle madness are contrasted against lines referring to the here and now. Dialogue describing the patient having written the works of Nabokov swerves wildly into discussions of how he was born from the Führer’s frozen sperm! The therapist reminds him of the treatment he is obliged to offer, Clozapine, before we are reminded of why we are here.

“My colleague and I worked on a training programme which almost eradicated Schizophrenia in…”

“Western Lapland. I know, it’s the name of the play we are in.”

This incredibly powerful, thought provoking play is unlike anything I have seen before.

Through the psychosis on show, the audience are suddenly and brutally aware of what has been happening. It is not an illness to display psychosis but rather the fear of outsiders who label the strange experiences of others. This we call schizophrenia, and throughout the first half the audience dissect every character’s actions, deciding who to label sane and who to label insane.

So, it was in the context of this extraordinary first half that the interval arrived, and for the first time in my experience, no one moved. Bewildered and confused, even the house lights coming up saw no reaction from the audience. If any of the audience had ever wondered what it’s like to be really star struck, this was it. Only when the usher returned to the auditorium to remind us that we could get up did anyone start to take notice.

On comes the second half and the ushers instruct us to enter the other half of the auditorium. We are now seated in front of the mother in her kitchen and the patient’s brother.

Throughout the first half, the mother had been painted as a madwoman. With the tone and volume of the actors perfected so that only very particular lines could be heard, the patient’s descriptions of his mother’s borderline personality disorder are only reinforced by the noises and silhouettes from beyond the partition.

If anyone had ever wondered what it’s like to be really star struck, this was it.

Now in the second half, the show restarts the dialogue where it had been twenty minutes into the first half. What seemed like madness when they could only be heard is now clarified through the details not visible to the other side. The image of the family comes across as deeply dysfunctional, but the mother still comes across as sane and loving where previously she appeared to be neither.

It is here that we are reminded for the second time of the words of the patient: “The fictional realm helps you unearth your problems.” As the show progresses, the audience’s confusion and unease has left them desperately trying to solve what is going on in the characters’ heads. However, in doing so, assumptions have been made and stereotypes have been grasped at which leave the patient powerless. In the show’s final moments, the partition is opened and a moment of family unity reminds us of what is really important; the support and love of the people around you, and an acceptance of uncertainty when tackling Schizophrenia.

The Eradication of Schizophrenia in Western Lapland might not be a classical masterpiece, but it is extraordinary in its own right. Did I enjoy the performance? No, but what it lacked in simple enjoyment it made up for in the way I was left speechless at the end. If you’re really the sort of person who wants a fun, entertaining evening out, avoid this show like the plague, but its exploration of the human psyche is unmatched by anything I have seen in recent years. All I can do is stand and cheer at the incredible work of Ridiculusmus. We might not have given the cast a standing ovation on the night, but when you’ve had your legs swept out from underneath you, a star struck round of applause will do.

The Eradication of Schizophrenia in Western Lapland is at the Battersea Arts Centre until 14th February. Tickets £15, £12 for concessions