Lucy Prebble’s The Effect was first staged in 2012, presented at Barrow Street Theatre in the Village in 2016, and then revived at London’s National Theatre in 2023. That revival now comes to the Shed. It is a psychopharmacological love story: Tristan (Paapa Essiedu) and Connie (Taylor Russell) are participants in a clinical trial for a new antidepressant, overseen by Dr. Lorna James (Michele Austin). Tristan is an extroverted working-class Londoner from Hackney with a mix of confidence and self-deprecation, while Connie is a more tightly wound, introverted psychology student whose participation in the study is apparently less about getting paid than about intellectual interest.