For his role in Birdy, Nicolas Cage played a disfigured veteran helping his friend from war recover in a psychiatric hospital. Cage was only 19 at the time, and prepared for his role by having his wisdom teeth extracted without anesthesia. He also spent day and night with his face bandaged for weeks, in order to feel the physical pain and discomfort of his character Sergeant Al Columbato.
These dramatic "live like the character" stories make me laugh. Adrien Brody sold off his stuff and moved to Europe with two bags to pretend to understand what it was like to be a concentration camp survivor. The key ingredient for all of them is missing...the reality of the situation and knowing that it's just all just pretend and going home to palatial digs when it's all done or in Brody's case, just going to an ATM and checking in to the most expensive hotel in Paris when you get tired of roughing it . All of this is just drama on and off the set.