Connie and Tristan are both strangers when they sign up for a medical trial to test a powerful new antidepressant. But with each dose of medication, their attraction to each other grows. Is it real, or fuelled by the drug? Are they both even on the drug? Psychiatrist Dr Lorna James has concerns, but her supervisor Dr Toby Sealey doesn’t seem concerned… So what’s really going on?

Written by award-winning playwright and screenwriter Lucy Prebble, The Effect is a celebrated play about love, sorrow and the different influences that can change us.