Pure Captures What It's Really Like To Have OCD In Your 20s

Meet Marnie. She's 24 years old. Finished university, moved back to her parents' house in a teeny tiny town in Scotland, and grappling with the familiar agony of what to do with your life in your 20s. We’ve been there. We know the struggle.

That ol' cliché about moving to London after you graduate to, you know, "find yourself" in the big bad city? Marnie takes that avenue too. She finds herself stood on the side of the motorway, snow up to her ankles and a giant rucksack strapped to her back, waiting for a coach to take her on the eight-hour journey down south. Superficial ambition and naïve optimism didn’t land her on this familiar path, though. No, Channel 4’s new comedy-drama (yep, it's a genre) Pure is also about a secret, overwhelming condition that pushed Marnie to the edge and onto that bus to the Big Smoke.

Marnie (Charly Clive) struggles with intrusive thoughts. The nature of them is relentlessly consistent: unwanted, x-rated thoughts of a sexual nature, which fill her mind and completely take over. It's a specific form of obsessive compulsive disorder, also known as 'pure O' – the 'obsessions' are the graphic invasive thoughts, and the 'compulsion' part manifests as mental rituals that interfere with how she goes about her day to day life. But when we meet Marnie, she doesn't know that there's a name for it. She also doesn't know that she's not alone in her suffering. As far as Marnie is concerned, there's something very, very wrong with her. To use her own brilliant words: "It's like The Sixth Sense but I don't see dead people, I see naked ones."

Just before we meet her awaiting her getaway coach, Marnie had been giving a speech at her parents' wedding anniversary party when, midway through, the intrusive thoughts started up again. This time, for the first time since they started, they involved her family. Paralysed by the disturbing image of snogging her mum, her dad going down on her best friend, and a room full of naked people she knows, Marnie reaches breaking point. She panics, runs out of the building and goes straight home to pack a bag and get the fuck away.

Unsurprisingly, she wants answers and hopes that London will be able to give her some. Marnie takes a room with disarmingly friendly Shereen (Sonia Sawar), the only person she knows in the city and someone she and her friends used to bully at school. She seeks medical advice for her condition for the first time and is told that, actually, she might just be sexually suppressed and is encouraged to "experiment". It doesn't quite go how you think it will. Marnie also considers whether she might actually be a sex addict, and so goes to join Sex Addicts Anonymous (they quickly realise that no, she's definitely not a sex addict) where she meets Charlie (Joe Cole), who has a porn addiction. To say she has a journey is a wild understatement.

Based on the memoir by Rose Cartwright, who spent years ashamed and keeping her sex-oriented intrusive thoughts secret, Pure very loosely follows Cartwright's journey of coming to understand and accept her OCD with very little information to help her out, all while navigating the trials and tribulations of her 20s. As we see through Marnie, her work life, relationships and sense of self are all thrown out of whack on both sides of her understanding what she's dealing with.

There's no shying away from the shocking and sometimes difficult topic matter, of course. Thankfully it's shows like these that prompt bigger discussions around lesser known mental health issues, without tokenising a condition for the sake of moving a story on – as Pure's writer Kirstie Swain noted, "in the past it's been a shortcut to an interesting character". But so much of Pure's greatness comes from those sincere laugh out loud (like, literally out loud) moments that make the familiar awkwardness of all our lives so much easier to bear. If you need convincing, let me just say that the first of Marnie's romantic interests starts rather naively at a bar, the second is halted by some bright blue vomit, and the third gives purposeful definition to the term "fapping".