“Side Effects,” opening Friday in Boston, is a psychological thriller set amid psychiatric offices and high-stakes pharmacology. There is a plot twist, then another, then, oops, Soderbergh has said too much already. The Oscar winner for 2000’s “Traffic” doesn’t want to give the quote that gives away a single one of the surprises in what he insists will be the last movie he makes, at least for some time.

“Here’s the problem,” Soderbergh says as a shrimp cocktail is delivered to the sofa where he is sitting in a high-end Beverly Hills hotel. “How do you sell a movie in which the best-case scenario for the audience is they know absolutely nothing? How do you convince people not to tell their readers anything? That’s the hard part.”

Soderbergh’s friend and frequent collaborator, screenwriter Scott Z. Burns, is game to try. He says he loves movies where the rug gets pulled out from under the audience, and is hopeful reviewers and filmgoers will treat his latest with the same respect they showed “The Crying Game” or “The Usual Suspects.” But those movies came out in the early–to-mid-1990s, before everyone was on the Internet and entire TV networks were devoted to celebrity gossip.

“I generally tell people: The best roller coaster rides go through familiar landscapes and show them to you in a new way,” Burns says about the plot he can’t disclose. “I would say: There are four really famous actors in this movie and someone gets killed, someone gets [lucky], and someone gets played. And that leaves one other person.”

The four actors are Rooney Mara, Jude Law, Channing Tatum, and Catherine Zeta-Jones. Mara plays a young woman depressed by her husband’s imprisonment for financial shenanigans and the loss of their lifestyle even after he’s released. Tatum is the husband. Zeta-Jones plays Mara’s first psychiatrist, Law her second. He’s the one who prescribes a made-for-the-movie anti-anxiety medication called Ablixa, complete with its own fake website (www.tryablixa.com) and unpleasant side effects. Good things do not happen. Unexpected ones do.

Burns spent almost a decade developing “Side Effects,” his interest in the intersection of psychiatry, pharmacology, and crime piqued by research for the controversial and short-lived TV show “Wonderland,” set in a mental institution. It was at New York’s Bellevue Hospital that Burns befriended Dr. Sasha Bardey, then deputy director of forensic psychiatry, and the two began collaborating on the movie. As he describes it, Burns provided the framework, Bardey the context.

“We’ve all seen more and more ads on TV and there are more drugs and obviously we live in a society where, whether you’re Lance Armstrong or the person at the next table at the restaurant, it’s become quite commonplace to take a pill for one reason or another,” Burns said. “What used to be a reasonable response to a set of events in your life has now become akin to being out of shape. It’s considered really unattractive to be sad or anxious and we don’t do a great job of differentiating between a justified state of sadness and a state of depression.”

Both Burns and Soderbergh can — and do — speak at length about psychiatry in general and the pharmaceuticals that have become the relatively inexpensive, go-to alternative to the talking cure. Even in separate conversations several days apart, the two exhibit a familiarity based on actual friendship, riffing off each other’s ideas and then advancing them.

Then again, they’ve worked together many times. Burns wrote and Soderbergh directed “Contagion” and “The Informant!” The “Side Effects” collaboration came about when another movie of theirs, “Man From U.N.C.L.E.,” fell apart. Soderbergh, who rose to fame with 1989’s “sex, lies, and videotape,” used that failure as an excuse to ask Burns once again if he’d let Soderbergh oversee his screenplay. Burns finally caved.