Do you really love me? That is just one of the big-ticket questions asked of a character in The Effect, a feverish piece of writing by award-winning playwright Lucy Prebble. Having worked on shows like HBO’s Succession, Prebble has a knack for capturing unsteady power dynamics and social realism. Winner of the Critics’ Circle Award for Best New Play when it opened at the National Theatre in 2012, The Effect seeks to scrutinize the world of modern medicine as it follows a pair of paid volunteers participating in a drug trial for an experimental new antidepressant. —B.A.