NEW YORK — Asked to come up with a motive for the myriad crimes of “American Psycho,” a theatergoer might conclude that the darkest, most diabolical desire of Patrick Bateman, the musical’s clean-cut lethal weapon, is to bore his victims to death.

No other rationale burbles compellingly to the surface to explain this slick and tedious adaptation of Bret Easton Ellis’s smartly provocative 1991 novel. If for no more engaging purpose, the musical materializes on Broadway, where it opened Thursday night at the Schoenfeld Theatre, as further evidence that horror is a genre that rarely mixes well with show tunes.

Stephen Sondheim and Hugh Wheeler did succeed grandly in this regard, in “Sweeney Todd,” and mock-horror has worked in the past courtesy of a plant named Audrey II and a laboratory monster called Rocky. (“The Phantom of the Opera,” meanwhile, falls a bit outside this realm and into the category of gothic romance.) Otherwise, Broadway has proved to be a graveyard for chiller musicals, a burial ground for ventures like “Carrie” and “Lestat” and “Dracula the Musical.”

As adaptive as the Broadway musical form can be, it frequently stumbles when the visceral response it seeks is terror. Is it that in any but the subtlest pieces, the gory excesses tend to look too contrived, or that a beautiful singing voice and rhyming lyrics don’t instill the right kind of fear (in musical lovers, anyway)?

“American Psycho” creates another sub-genre — ersatz horror — an odd variation that fails to tingle your spine with its copious bloodletting or titillate you via the writhing bodies in its mechanical sex scenes (complete with pornographic video illustrations). Director Rupert Goold’s shiny production, churning vapidly to the beat of composer Duncan Sheik’s surprisingly clunky, characterless songs, charts the homicidal rampage of Patrick (Benjamin Walker) through the cash-engorged precincts of the Manhattan of the decadent ’80s; Es Devlin’s eye-catchingly sleek sets are the production’s best asset. And then, in an odd departure from the novel, Roberto Aguirre-Sacasa’s script pulls the blood-soaked rug out from under us, with the suggestion of a Patrick reborn, as a better man.

Patrick appears early in the show to us as a perfect Wall Street killing machine — a psychopath who trades in his lust for the best accounts for the more primal sensation of eviscerating anyone who gets on his nerves, from an unfortunate vagrant (Keith Randolph Smith) to a fatuous workplace rival (Drew Moerlein). Since virtually everyone in Patrick’s world is pure caricature, we give not one hoot whose carotid artery he severs.

Except, of course, if the blood vessels belonged to Patrick’s sweet, soft-spoken assistant Jean (Jennifer Damiano), whose impression of charmless Patrick as sensitive and caring is an incitement itself — to vigorous audience eye-rolling. (Damiano, like fellow “Next to Normal” alumna and Tony-winner Alice Ripley, playing Patrick’s mother, seem here as if they have been accidentally assigned to a classroom below their grade level.)

Much of “American Psycho” concerns itself with the vacuous rewards of a high-flyer’s life; its black comedy component posits that Wall Street’s carnivorous capitalism is the perfect arena for a remorseless serial killer. If the satire were more stinging, the show might stand a chance. But the machinations are neither scary nor funny: the depictions of acquisitive Manhattanites sniping at pretentious dinner parties and dancing away at downtown clubs recycle images you’ve seen a thousand times before.

The musical trades, too, in lame, ’80s pop-culture-inspired sight gags, as in a scene devised solely to make fun of Tom Cruise’s height. The songs blandly drop the names of expensive brands and fashion labels, as an ensemble under choreographer Lynne Page’s guidance executes the robotic moves of frenetic music videos.

Walker, who a few seasons ago magnetically anchored the raucous political satire “Bloody Bloody Andrew Jackson,” is again the front-and-center attraction in this show, to far less mesmerizing effect. Wearing the mask of Patrick’s smugness, Walker comes across as little more than a fitness model with presence and a great voice.

And as he’s naked from the waist up for large portions of the evening — and stripped down to bloody tighty-whities for most of Act 2 — he’s given ample opportunity to show off the advantages of weight training. This raises the possibility that after the run of “American Psycho” ends, it could be repurposed as an exercise DVD.

—

“American Psycho,” book by Robert Aguirre-Sacasa, music and lyrics by Duncan Sheik. Directed by Rupert Goold. Choreography, Lynne Page; sets, Es Devlin; costumes, Katrina Lindsay; lighting, Justin Townsend; sound, Dan Moses Schreier; videos, Finn Ross. With Helene Yorke, Alex Michael Stoll. About 2 1/2 hours. Tickets, $69-$250. Schoenfeld Theatre, 236 W. 45th St., New York. Visit telecharge.com or call 212-239-6200.

stage-psycho-review