Split

You know the big twist is coming, and it’s not going to be what you think. That’s inevitable because Split is the latest project from writer-director M. Night Shyamalan.

The filmmaker behind The Sixth Sense and Unbreakable is up to some of his old tricks in this slow-burning psychological thriller that recombines some familiar themes into a new package. Except this time, his exploration of mental illness and residual childhood trauma lacks depth beyond its slick narrative gimmicks.

Kevin (James McAvoy) suffers from dissociative identity disorder — or multiple personalities — that turns him from playful to malevolent, from mild-mannered to maniacal in mere seconds. We don’t know much else, other than his reliance on a respected therapist (Betty Buckley) who acts as a sounding board for his struggles.

Of course, Kevin has a darker side to many of his 23 personalities, with threats to unleash a 24th known only as The Beast. That coincides with the abduction of three teenage girls, including best friends Marcia (Jessica Sula) and Claire (Haley Lu Richardson), along with a troubled outsider (Anya Taylor-Joy) who might have their best plan for escaping their captivity.

McAvoy propels the material forward by turning the film into his own personal acting workshop. He impressively juggles more than a half-dozen roles within his singular character, sometimes within the same shot. Even if the personality shifts too often seem arbitrary in their timing, McAvoy’s portrayal carries a sense of energy and offbeat humor.

Even if the screenplay is deliberately paced, Shyamalan generates some moderate suspense. He deserves credit for not relying on cheap thrills or genre clichés, although the whole thing feels manipulative, as though the filmmaker is withholding key details for the primary purpose of confusing the audience prior to the big reveal.

In assuming moviegoers will just roll with it, the film leaves some logical gaps — such as why the man is not institutionalized — that are only partially solved by the third-act twists. By that time, those who haven’t bought in will have relinquished their emotional investment.

As a result, Split is a mildly unsettling but never truly frightening puzzle of a thriller that develops only intermittent tension as it seeks to find a personality of its own.

Rated PG-13, 117 minutes.