Leonardo DiCaprio has admitted that he found the Shutter Island shoot very traumatic.
The actor reunites with Martin Scorsese, their fourth collaboration, for the psychological thriller.
In an interview with Parade the actor said: "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.
"It was really very traumatic, and I don’t say that about a film very often. I went to places and unearthed some things that I didn’t think I was capable of.
The movie is based on the Dennis Lehan novel and DiCaprio stars as US marshals Teddy Daniels who is ordered to investigate the disappearance of a patient from a mental hospital on Shutter Island, a remote outcrop some 11 miles off the coast of Boston.
The missing patient is Rachel Solando, a murderess who seems to have defied the high security in the hospital and vanished into thin air.
As Teddy begins his investigation, he starts to unearth some sinister goings on but it becomes clear that nobody, including the hospital's enigmatic chief is willing to talk.
The movie brings together a great cast including Mark Ruffalo, Ben Kingsley, Emily Mortimer and Michelle Williams.
Shutter Island is released 12th March.
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