The Effect was written by Lucy Prebble in response to the tragic events in a North London drug trial in 2006, where many of those participating developed multi organ failure as a consequence of the drug being tested. In fact, Prebble subsequently volunteered for a drug trial, to understand more about the processes involved. When settling to write the play, Lucy developed the part of Connie specifically for her friend, the actress Billy Piper, as she knew Billy would be ideal to play her complex, flawed character.

The demanding four character portrayal of the issues surrounding clinical drug trials of a new antidepressant focuses on the developing relationship between Connie, a young psychology student and Tristan, who is also on the trial. Are the feelings which they are experiencing due to the drugs or are they real? Does it truly matter?

The subject matter of depression and the issues surrounding it is relevant to everyman - one in four of us will suffer the illness at least once in our lives. Statistically, most people will have either suffered the condition, or be close to someone who has.

The Effect raised some tough issues and leaves the audience to grapple with them, as there are no answers. Is depression really an illness? Or are clinicians guilty of over medicalising normal emotional responses? Are pharmaceutical companies inflating their profits by encouraging prescribers to respond to unhappiness rather than true depression? Are some victims of depression resisting treatment? Ironically, this is demonstrated by Dr Lorna, a psychiatrist, who denies the biological basis of depression, but suffers worsening of her own depressive symptoms, leading to her inability to function.

The subplot, exploring the cruel world of research where philandering research chiefs fly round the globe giving the same lecture for decades, may resonate with the academic audience at Keble. If all this sounds to heavy, don't be put off, there are moments of brilliant witty humour which add depth and balance.

For me, the stand out performance was that of Callum Lynch, playing Tristan - for sheer believability, and a wonderful brogue!

But be warned, certain scenes may make uncomfortable viewing for those with squeamish or prudish dispositions.