DiCaprio, 35, said the pressures behind filming the drama were rooted in the film's themes regarding the mentally ill and the use of insane asylums, Parade Magazine reported online Friday.
"I have to say Shutter Island was one of the most intense, hardcore filming experiences I've ever had as we explored what the mentally ill had to face in the days when mental hospitals were called insane asylums," DiCaprio said. "It was really very traumatic, and I don't say that about a film very often."
DiCaprio told Parade that helping bring the book written by Dennis Lehane to the big screen did give him another chance to work with Scorsese.
"If you'd asked me at sixteen the director I wanted to work with, it would have been Marty. So I couldn't wait to be in one of his films," said DiCaprio, who also paired with Scorsese on "The Aviator," "The Departed" and "Gangs of New York."