Leonardo Dicaprio became a mental illness expert while researching his new thriller SHUTTER ISLAND - by spending hours watching dark documentaries.
The actor plays a detective trying to solve a missing persons mystery in an asylum in the new Martin Scorsese movie, and decided to study the mentally ill to perfect his role.
But admits he maybe took his homework a little too far: "There was a tremendous amount of research done involving the entrapments of mental illness and the suffering that people go through, so it led me to watch a lot of different documentaries on mental illness.
"For a few weeks there, it was some of the most hardcore film experiences I've ever had. It was like reliving trauma in a way. It was pretty intense."
And the intensity didn't stop when filming began.
DiCaprio tells WENN, "We were surrounded by it (mental illness) every day. We were surrounded by dilapidated walls of an old mental institution. We had somebody there who was guiding us through the history of mental illness, the pathways of treating it and the different forms of treatment."