SHUTTER ISLAND
Shutter Island is a 2010 psychological thriller film starring Leonardo DiCaprio as US Marshal Edward Daniels. The plot happens in 1954 and it is about two U.S Marshals:  Edward (Teddy) Daniels and his new partner Chuck Aule investigating a psychiatric facility on the island because of the disappearance of one patient incarcerated for drowning her three children. After the arrival because of the storm the Marshals couldn't leave to the mainland and the staff of the hospital was confrontational as if they had some secret.


As the investigation continues Daniels and Aule find out that the lost patient was already found by the staff with no explanation. Getting suspicious, Daniels breaks into the prohibited part of the hospital and meets another patient under the solitary confinement who reveals Daniels that the hospitals is doing strange experiments on its patients. The ending was surprising. Chasing after each clue, Daniels gets more and more sick and confused. Things go out of his control. Eventually he has to learn that Daniels himself was a patient who went insane.
 In 2011 I went on a work and travel program to the US and I watched Shutter Island in the evening of the day I arrived in the Martha's Vineyard. The movie begins showing an island and the title says "Massachusets, Somewhere near Boston" which made me hope that there is no actual psychiatric facility near the Martha's.

https://trailers.apple.com/trailers/paramount/shutterisland/
Source:http://en.wikipedia.org/wiki/Shutter_Island_(film)