The Effectquestions medicine at its highest level: neuroscience. We rely so much on what scientists tell us – if we are ill we trust them to give us the cure, and we do what they say in the belief it will make us better. Especially when it comes to brain studies it’s hard to question the facts,  because what do we “normal” people know about the mechanics of our brain other than what we’ve been told by scientists? This is the premise underpinning Lucy Prebble’s (ENRON, Royal Court) new play.

A team of doctors is testing an anti-depressant on volunteers in a closed environment, increasing the dose gradually to test the effect of the new drug. Desperate to find a cure for depression they try to push the truth in the right direction even though the results suggest otherwise: that maybe not all scientific facts are true and that not everything can be cured by drugs.

Connie (Billie Piper) and Tristan (Jonjo O’Neill) are total strangers who allow the scientists to experiment on their bodies with the new anti-depressant. What they didn’t expect to happen was chemistry exploding between them – they’ve found their anti-depressant not through drugs, but through the madness of falling in love.

As we follow the trialists’ journey through the body’s crazy reactions to falling in love, Prebble asks whether life’s great ups and downs can be controlled by the chemical industry or if some things are just not meant to be messed with by drugs. As the doctors try to play god, Prebble indicates that maybe we shouldn’t accept all scientific facts as definitive.

The Effect is piercingly beautiful, straddling solid facts and creativity, with an immaculate understanding of human beings and dialogue. It’s dynamic, daring and enlightening and takes us through an emotional and almost childish journey of falling in love properly for the first time. Piper is enigmatic and full of soul as the practical Connie and matches O’Neill’s honest and liberating Tristan, and together they create that rare spark of complete honest chemistry on stage which is just a joy to watch. All the actors inhabit the intimate space of the Cottesloe with such energy that it’s impossible to take your eyes off them. Especially Anastasia Hille’s decaying Doctor Lorna is heart-breaking as she succumbs to depression herself after being crushed by love.                  

The play seems a tad slow at the beginning but this is all part of director Rupert Goold’s (Artistic Director of Headlong) master plan – the audience is slowly lulled into the world of the experiment and then with a bang we are thrown into the raging dopamine-rush of the trialists and their response to the drug, whether this be chemicals or the drug of love. Goold’s direction is sharp, chaotic and impulsive like his characters and is a thrill to watch. It’s honest and beautiful and honours Prebble’s clever, bold writing.

Depression is one of the darkest paths our minds can take us down. Love on the other hand throws us into a blend of happiness and sweet insanity, and the play argues that neither should be seen as a disease that can be cured and corrected, but as something human, something that’s a part of all of us. If the brain is just a brain that you can manipulate with drugs, then where does that leave the soul? The Effect is the kind of play that will stay with you, haunt you and nurture you a long time after the curtain falls.

The Effect is playing at the National Theatre’s Cottesloe until 23 February. For more information and tickets, see the National Theatre website.