Madness
Madness is central to the plot of Shutter Island, a film that takes place entirely at a mental hospital. The protagonist Teddy Daniels is trapped in a delusion for nearly the entire film, only able to acknowledge the reality of his past for mere moments before regressing back into his delusional world. Teddy's line at the end of the film—"Is it better to live as a monster or die as a good man?"—suggests that death might be preferable to the kind of "mad" existence that Teddy inhabits after the traumatic events he has endured. Teddy's madness is linked not only to the circumstances of his family's deaths, but also to his military service in World War II, during which he witnessed the horrors of Nazi death camps. Scorsese implicates the viewer in Teddy's madness by grounding the film's perspective almost entirely within his delusional mind.
Performance
Shutter Island is, among other things, a meditation on the therapeutic powers of performance and performative role-play. As Ashecliffe's head doctor, Dr. Cawley essentially "directs" every move that the doctors, wardens, and patients make over the two days during which the film unfolds. Cawley's performance means that every employee and patient must play a role in Teddy's fantasy, a plot device that Cawley invokes early in the film when he mentions that Rachel Solando's delusions have taken on an elaborate "fictional structure." Teddy's paranoid feelings are in a way valid, given that everyone around him is conspiring to help him break through his psychosis and recover the memory of his previous trauma.
Dreams
Teddy suffers several migraines over the course of the film, which cause him to have strange dreams in which his dead wife Dolores appears. Dr. Naehring tells Teddy near the end of the film that the German word for dream, "traum," derives from the ancient Greek word meaning "wound," in an attempt to make Teddy realize that his hallucinations are preventing him from confronting repressed traumatic memories. Teddy's tragic past as Andrew Laeddis also causes him to imagine the character of Teddy Daniels, and to essentially exist inside a dream-world where he is a U.S. Marshal investigating a disappearance. Cawley, by engaging all of Ashecliffe in a collective performance, is in effect helping Teddy act out his "dream."
Trauma
Set in 1952, Shutter Island takes place during a time when the entire world was recovering from the trauma of World War II. References to historical atrocities like concentration camps and hydrogen bombs are integrated into the film's screenplay, as are representations of incineration and drowning. In his former life as Andrew Laeddis, Teddy is implied to have been an alcoholic as a result of the horrors he witnessed while liberating Dachau. Cawley seeks to ease Teddy's trauma-induced delusions through "radical, cutting-edge role-play," rather than perform a trans-orbital lobotomy. At the end of the film, however, Teddy seems to prefer the lobotomy over having to keep re-remembering the traumatic circumstances of his wife and children's deaths.
Truth
Martin Scorsese directs Shutter Island so that the true nature of events are exceedingly difficult to discern, especially on a first viewing. At first, the film seems concerned with U.S. Marshal Teddy Daniels's search for the truth, especially as it concerns the disappearance of Rachel Solando and the arsonist who killed his wife, Andrew Laeddis. However, at the end of the film, Teddy learns that it was in fact his wife who was a suicidal arsonist, and whose murder of their children led him to become committed at Ashecliffe. The illusion surrounding Teddy crumbles when he is forced to confront these revelations inside a lighthouse—a symbol throughout the film for illumination and disclosure. Teddy's inability to confront the truth in a sustained way is what forces Cawley and the rest of the medical board to recommend him for a trans-orbital lobotomy.
Violence
Many of Martin Scorsese's films grapple with the moral relationship between masculinity and violence, and Shutter Island is no exception. Teddy seems to draw a firm line when he tells Chuck that his experience serving in World War II taught him that warfare is tantamount to "murder." However, both Dr. Naehring and a nameless warden accuse Teddy of being a "violent" man at heart, a reference to the fact that Teddy executed his wife with a pistol after finding that she had drowned their three children. Teddy also attacks George Noyce after Noyce calls him "Laeddis," which causes Ashecliffe's medical board to become apprehensive over his recovery prospects. Knowing Teddy to be violent, Cawley gives him a fake gun when allowing him to act out his delusions.
Memory
Although it contains many red herrings, Shutter Island is ultimately about how Teddy Daniels is unable to cope with the memories of his former life as Andrew Laeddis. Many of the film's early scenes recast key details from his repressed memories, such as the first Rachel Solando's speech, Mrs. Kearns's interview, and Teddy's first and second dreams. Teddy fragments and reassembles the pieces of his repressed memories, turning the name "Andrew Laeddis" into "Teddy Daniels," and "Dolores Chanal" into "Rachel Solando." He also transforms his memory of his three children's deaths into a memory about George Noyce killing three people in a bar fight. Because Teddy's actual memories are too painful for him to live with, he decides to undergo a lobotomy procedure at the film's close.
