Review: If two people fall for each other during a clinical trial, is it love or the drugs?

As he encounters his first ghost, cartoon miser Scrooge famously said: “You may be an undigested bit of beef.”

Connie, a young woman who has been sequestered in a clinical trial for antidepressants, has a similar question as she falls for fellow subject Tristan. Is their developing passion an expression of true love powered by naturally occurring dopamine or the side effect of the increasing doses of psychotropic drugs administered to them?

Connie (Becca Claire Hart) and Tristan (Kamani Graham) are two of the four characters in Lucy Prebble’s provocative play, “The Effect,” which opened in a regional premiere over the weekend at the Jungle Theater.

Prebble, famous for writing and producing the HBO series “Succession,” first wrote “Effect” in 2012. She has since revised it, updating elements and adding seemingly random American references — Tristan is from Louisiana and Connie from Delaware.

The beginning is a bit of clunky exposition. Isolated in a compound where they have no contact with the outside world, Connie and Tristan grow increasingly close. But Connie has a boyfriend back home.

The young people have a mirror in Dr. Lorna James (Christina Baldwin), who administers the drugs, and Dr. Toby Sealey (Greg Watanabe), a business owner.

Director Alison Ruth’s production is well acted and compelling. She orchestrates the 90-minute one-act as a tense interplay between cold, scientific precision and the messy things of the human heart and soul.

Dressed in ordinary attire, Graham and Hart rely on acting, not sex appeal, to power their work. And they both perform beautifully, recalling the joy one feels about watching Kendrick Lamar’s halftime show at the Super Bowl this year with excellent artistry and nary a suggestively half-naked body in sight.

Watanabe is stately and steely as Toby, a figure limited by business goals but one that’s understandable nonetheless.

Returning to the stage after many years, Baldwin is captivating as the doc, investing the character with sure-footed authority and nuanced vulnerability.

“Effect” raises some big issues, many illustrated with theatrical flair. Like, where in the body does a human soul lie?

That age-old question is joined with fresh urgency when Toby reaches into a bucket during a lecture and retrieves a wet, gleaming brain. He holds it up like a newly unearthed precious stone for the audience to see.

The play also takes the pharmaceutical industry to implicit task, not by tut-tutting about it being blinded by profits but by showing how even those in charge become the sort of subjects that ordinary civilians are accustomed to being.

In one of the play’s most troubling scenes, Tristan has a shocking outburst. But is that because of his nature? Or could it be a side effect from the regimen of dosages?

That riff on the nature-vs.-nurture debate plays out on Benjamin Olsen’s half-shell set, which resembles an oversized science classroom with chairs on three sides that is lit almost like some weird dream by Shannon Elliott. As “Effect” only has four characters, the empty seats serve as an invitation for the many who the prescription drug industry wants to get as customers. The chairs also are suggestive of ghosts.

The Jungle’s design team, including costumer Sarah Bahr, sound designer Dan Dukich and projections designer Leslie Ritenour, creates an environment redolent of industrial science experiments, with lab coats and drab costumes, plinking sounds and projected graph monitors.

The theatrical result is one of distance and depersonalization. But the actors keep bringing it back to the heart, a tension that ripples throughout the play.

Like ants, we may be creatures guided by chemical signals. But as the story unfolds in “Effect,” the messy passions of people remain irrepressible.

When: 7:30 p.m. Wed.-Sat., 2 p.m. Sun. Ends March 30.

Where: Jungle Theater, 2951 Lyndale Av. S., Mpls.

Tickets: $15-$95 or pay-as-you-can. Jungletheater.com.