“Ask me who’s in charge” says Connie (Zoë Robbins) to Tristan, the man she meets during a clinical trial for an experimental anti-depressant to which they have both leant their bodies for four weeks. There’s an instant spark from the moment they cross paths, each with a fresh urine sample in hand. Same birthdays, both nail biters. He’s East Coast and she’s from the Hutt. He’s cocky and blasé (and oozingly charismatic played by Jayden Daniels). She’s nervy and eager to pass the psych assessments, so just enough difference to keep things interesting (as Hilton Als recalls a lover once saying to him, People don’t fuck because they agree with each other.) Why do they fuck, flirt, fall in love? 

The Effect circles these questions (as well as Connie’s, but more on that later)—a bad verb here given the production designer’s proclivity for the square. A white LED beam bisects the stage for much of the show, turning it into a rink—a sweet shorthand for the bounded and surveilled space of the clinic, if somewhat of a poor man’s version of the dazzling white-light flooring of the recent London staging, likened by one reviewer to a Petri dish. Time, too, is allotted into neat blocks. Dose One, Two, Three and so on, announced on each occasion by a dense techno drone (from sound designer, Chelsea Jade) and a large screen showing the increasing measures like a countdown to something, probably terrible. My seatmate, Art News Editorial Director Becky Hemus, remarked that 50MG spelled out in the show’s bony alarm-clock font (mis)reads as SOMA, recalling the ubiquitous pleasure-drug of Aldous Huxley’s Brave New World, famously boasting “all the advantages of Christianity and alcohol; none of their defects.” Whether or not this was intentional on the part of the production team, the reference largely aligns with the position taken by playwright Lucy Prebble on psychosomatic pharmaceuticals, which is sceptical of the industry agenda but seduced by its object of study: the dark, delicious continent of human feeling. 

Love potions are canonically ill-advised. ‘Venom’, Lisa Perrin writes in The League of Lady Poisoners, likely owes its etymology to Venus and venenum, meaning “magical charm, potent drug.” Eminent victims include the Greek poet Lucretius, who in Tennyson’s account was poisoned by his wife, jealous (“wrathful, petulant”) of his passion for poetry, who turned to a local witch in the hope of redistributing his attentions, brewing a “wicked broth” that drove him to madness then suicide. Prebble advises the same caution when it comes to anti-depressants. Supervising Connie and Tristan are two doctors, Dr Lorna James (Sara Wiseman) and Dr Toby Sealy (Jarod Rawiri). Lorna is the project-lead with a personal history of depression; or, less damningly, so she seems to think, perennial ‘depressive episodes’. Toby is a doctor-cum-spokesperson for Raushen Pharmaceuticals, there to support, and monitor, Lorna. She’s dressed in a crisp white shirt and loose camel slacks with a matching suit vest (very Esther Perel). He wears a short-sleeved shirt, desert boots and shorts with a matching safari jacket (very Nigel Thornberry). The two share a murky romantic history meant to mirror the one growing between the two young lovers, its sallowness perhaps meant as a sign of what’s to come when love loses the warm glow of the new, as well as the doctors’ fallibility in the matters of feeling to which they’re playing God. 

The flirtation and sexual tension between Connie and Tristan soon becomes a problem for the trial: is the heightened brain activity of the two subjects evidence of the drug’s effectiveness, or is it the stirrings of a new crush? Likewise the trial becomes a problem for the couple, not least because the dorm rooms and physiological monitors make it difficult for them to act on their desire. More concerning for the pair is whether their connection is genuine or a side-effect of the drug and the clinic’s enclosure. Even worse: what if one of them is on a placebo while the other is flush with artificial dopamine? This double-helix is The Effect’s pulsing centre, while medical ethics and the gamification of human relationships come sometimes glintingly, sometimes piercingly under its security through dialogue (“there’s no such thing as side effects, only effects you can’t sell”), through set and sound design (the beaming lights and text banners recall the dating show gimmick of AI ‘matchmaker’ software) and through intimacy direction (carefully choreographed into a series of vignettes, though this registered slightly awkwardly as sex-as-theatre sports).

So, who’s in charge? Prebble seems to think no one, really. From the second act, the controlled environment of the trial begins to come undone, Dr James’s carefully planned procedures are toppled by Connie and Tristan’s fawn-legged, disaster-bound romance and her own growingly-fragile mental state. If anyone’s coming out on top it’s probably the pharmaceutical company bank-rolling the whole thing. The Effect was most interesting when trying to grapple with and aping the language of medical capital (that even darker continent), as in a brief interlude when Dr Sealy addresses the audience stand-up-style to tout the recent breakthroughs of psychosomatic therapies and preach the importance of mental hygiene, all while brandishing a brain produced like a magician’s bunny from a plastic bucket that he claims belongs to his own father, who donated it to science. Something for the heart-strings, something for the prefrontal cortex. The thing is now that there’s really no difference.