Written by Lucy Prebble, The Effect was met with widespread critical acclaim when it premiered at The National Theatre in 2012. Having unfortunately missed that original production, I was delighted to have the opportunity to experience this intimate and compelling revival at the Old Red Lion Theatre.
Directed and produced by Sam Edmunds and Sara Odeen-Isbister, with assistant producer Niamh Grace, this production had the unenviable task of following this celebrated contemporary play. Happily, it rises to the challenge with intelligence, sensitivity and confidence.
Connie (Millie Smith) and Tristan (Shadrach Agozino) meet while participating in a clinical drug trial for a new antidepressant. Both have signed up primarily for financial reasons – Connie to help support herself through university, and Tristan to fund his travels. From the outset, there is an undeniable spark between them. Their flirtation is natural, funny and increasingly heartfelt. Yet there is one crucial question at the centre of their relationship: are their feelings genuine, or are they simply a side effect of the experimental drug, designed to increase the brain’s levels of dopamine and other neurotransmitters associated with pleasure and happiness?
Prebble’s brilliantly constructed script constantly blurs the line between authentic emotion and chemical stimulation, asking whether love itself can ever be separated from biology. If our emotions are driven by brain chemistry, is falling in love anything more than a neurological response? It is a fascinating premise, explored with wit, humanity and emotional honesty.
Millie Smith gives Connie an engaging vulnerability beneath her fiercely defended independence. Intelligent and self-assured, Connie nevertheless carries an underlying melancholy that Smith reveals with subtlety and warmth. Shadrach Agozino’s Tristan is charismatic, playful and optimistic, his easy charm making it entirely believable that Connie would be drawn to him. Their chemistry together feels utterly authentic, making the central dilemma all the more affecting.
Their playful exchanges are among the production’s highlights. Tristan gently teases Connie’s insistence on her independence, amusingly invoking Beyoncé’s anthem of female empowerment. These moments of humour are charming while simultaneously revealing the emotional barriers both characters struggle to overcome.
Running alongside the romance is the equally compelling relationship between the doctors overseeing the trial. Dr Lorna James (Sara Odeen-Isbister) and Dr Toby Sealey (Andrew Pearson-Wright) are former lovers whose unresolved emotional history continually threatens to undermine their professional judgement. When it becomes apparent that Connie and Tristan have entered into a sexual relationship, the ethical foundations of the trial begin to crumble. Are the drugs influencing their behaviour, or are they simply revealing feelings that already existed?
Odeen-Isbister delivers a nuanced performance as the emotionally guarded Lorna, whose clinical detachment masks deeper personal struggles, while Pearson-Wright brings quiet authority and conviction to Toby, whose certainty is gradually challenged. Together, they convincingly portray professionals wrestling with questions for which science still has no definitive answers.
The production asks profound questions about the limits of neuroscience, the medicalisation of depression, and the extent to which modern psychiatry can truly explain the complexities of human emotion. It challenges the audience to consider whether love, happiness and sadness are merely biochemical processes, or whether something more mysterious lies at the heart of what makes us human.
All four performances are outstanding. Smith and Agozino as two young people navigating the uncertainty of young love under extraordinary circumstances, while Odeen-Isbister and Pearson-Wright provide a compelling counterpoint as the experienced psychiatrists whose confidence in science is tested by the unpredictable reality of human behaviour. Their authority carries an unsettling edge, raising uncomfortable questions about the ethics of experimenting on vulnerable people while acknowledging how little we still understand about the workings of the human brain.
Thought-provoking, emotionally absorbing, and frequently funny, The Effect remains as relevant today as when it first premiered. This production is superbly acted, expertly directed, and intellectually stimulating, leaving audiences with questions to ponder. A thoroughly entertaining and deeply captivating evening of theatre that is highly recommended.
Review by Bernadette Lintunen
Two young volunteers, Connie and Tristan, fall for each other while taking part in an antidepressant trial. Their chemistry is undeniable – but is it real or a side-effect of the drug?
Overseeing the experiment are doctors and former lovers, Lorna and Toby, whose professional disagreements about depression and medication expose fractures in their own relationship.
Connie Hall – Millie Smith
Tristan Frey – Shadrach Agozino
Dr Lorna James – Sara Odeen-Isbister
Dr Toby Sealey – Andrew Pearson-Wright
Director – Sam Edmunds
Producer – Sara Odeen-Isbister
Assistant Producer – Niamh Grace
Movement Director / Intimacy Coordinator – Jess Tucker Boyd
Set Design – Rob Miles
Lighting Design – Sam Edmunds
Sound Design – Gabriel Burns
THE EFFECT
By Lucy Prebble
Old Red Lion Theatre
30 June to 11 July 2026
