Leonardo DiCaprio knows how to screw with people.

After a slow 2009, DiCaprio returned in 2010 for some of his most cognitively complex work to date. He took the lead in two of the year’s biggest films: Martin Scorsese’s thriller “Shutter Island” and Christopher Nolan’s head trip “Inception.” In both cases, the actor created characters rich with idiosyncrasies — as moviegoers blindly trusted them, only to have that trust betrayed at the drop of a hat.

“They were selfish and deceived the audience, caught up in their own psychosis,” he says.

At least “Inception” was more upfront about that trickery. DiCaprio plays Cobb, a specialist who infiltrates people’s dreams and then steals or implants valuable information. The task requires him and his team to escort the subject into many dreams-within-dreams; the deeper they get, the more the mission is jeopardized.

DiCaprio had to keep close tabs on his character, despite there being “times on set — between five levels of the dream state — that my mind got twisted like a Rubik’s Cube,” he says. When he signed on, “The script was very much a work-in-progress” but DiCaprio says he trusted the process because of Nolan’s vision.

Same goes for his work with Scorsese, now a frequent collaborator. The Hitchcockian “Shutter Island” is the story of an emotionally disturbed detective unraveling an unnerving mystery at a mental hospital.

“It was challenging because we essentially did the character in three different levels of intensity,” he says. Much of the perf came together in the editing room — a sign of ultimate faith in a director.

Though both characters share similar qualities, DiCaprio was careful not to mirror his work on one or the other. He has become adept at the infinite shades of insanity, and it’s bringing out some of his best work.

“In both cases you’ve got an unreliable protagonist, which is of fun to play,” he says. “You get a pair of aces.”

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