Seeing Grey Matters is not like the usual theatre experience. From the cast and the scripting to the very staging and the venue(s) at King’s College, the audience is thrown quite thoroughly out of their comfort zone. It would be easy to imagine this show falling into the trap of preachy inapproachability as we reach the end of Mental Health Awareness Week and enter Eating Disorder Awareness Week; it is, after all, set at a fundraiser for a theatre group made up entirely of those with mental health issues. Fortunately, Grey Matters is a superb dramatic experience.

A great deal of creative work that deals with mental illness accidentally tries overtly to shock, or romanticises its subject matter. One of the qualities that makes Grey Matters unique is its ability to deftly sidesteps these pitfalls. Though it begins with a glib adaptation of Hemingway’s famous ‘write drunk, edit sober’ manifesto – ‘write manic, edit depressed’ – it is ultimately a well-rounded portrayal of what it is like to live with mental illness, including the well-judged disclaimer that they can by no means speak for everyone.

The event starts off as any show might, neatly staged with clear seating and a clear audience, before descending into wonderfully farcical chaos. As of the end of the first act, the audience can't quite be certain what is scripted and what is improvised, what is autobiographical and what is imagined; what is real and what is staged. This is immersive theatre: immersive like having your head plunged under water unexpectedly, and then, just as unexpectedly, released. You are launched from light-hearted hilarity into dark, contemplative sobriety in the blink of an eyelid; at times the juxtaposition of humour and complexity would challenge even the best satire. The whole production serves to throw you completely off balance, disorientating you until you even start to question who is part of the cast. Was that shaky acting or beautifully polished delivery?

The performance itself evolves in three parts. The audience are moved from the opening act in the dark antechamber into a bright and bustling hub of cabaret, accosted by intriguing character after character. The main entertainment – the second act – begins with an amusing ditty (‘Cinderella and the Glass Ceiling’) from compere Monty (Marcus Martin), before diving into a powerful film on bipolar disorder and a beautifully constructed spoken word poem on schizoaffective disorder. This film is a cinematic work of art, making clear yet tactful use of the possibilities of sound and editing; and it is also a deeply affecting and relatable account of what it is like to suffer from bipolar disorder. The third act plunges you back into the darkness of King’s Bunker, surrounded by written accounts of mental illness.

This is not theatre for the fainthearted, but that should not put you off. Somehow, this student script has grown into the most accessible portrayal of mental illness I have ever encountered without trivialising the subject. It is a rare production indeed which can successfully harness and present schizoaffective disorder on stage, particularly in the same breath as bipolar and eating disorders. If you leave this remarkable production in tears, don’t worry – you won’t be the first.