Donnie Darko as Suicidal Ideation Allegory, Twilight Override (Jeff Tweedy from Wilco)

Narratively, cinema tends to oversimplify the onset of a character's mental illness by rooting it tidily in a single trauma. This is called the "presumption of traumatic etiology", a term used by Steven E. Hyler, MD, Professor of Psychiatry at Columbia University Medical Center, in his Comprehensive Psychiatry article, "DSM-III at the Cinema." In the mythos of the film, Donnie Darko must sacrifice himself to save the universe. In another read, though, he instead comes to the unfortunately common conclusion that his suicide will improve everyone else's lives. He allows the jet engine to crush his bedroom with him inside: he kills himself. Just think of the image at the end of the jet engine falling through the wormhole tunnel. What does that resemble? A bullet traveling through a gun barrel. The jet engine's rounded, cylindrical, shiny-metal shape is completely analogous to that of a bullet. The jet engine missing him the first time might be symbolic of giving up on an early suicide attempt. 

The suicidal young man's idea of himself as a hero who must sacrifice himself to save people is the psychology that is represented in many works (including Catcher in the Rye), and in certain mythology of rock and roll. Jeff Tweedy from Wilco differs from that mythology. Jeff Tweedy (talking over his most recent triple album Twilight Override): “I’m not espousing the dark underbelly of New York's nightlife or decadence or anything like that because I was so disappointed—even as an addict, I was so disappointed with the cliche of it, the hypocrisy of it. The disgusting nature of advocating for things that are really bad for people.  You know, honestly, the way rock and roll was marketed as a culture was just awful. And the part that I knew was there and was disappointed to find wasn’t really the guiding principle was the part that I thought was really beautiful.”

 

“It was just like, ‘Oh, you get together with your friends and then the world is a little less painful. You get together with your friends, make some music and you’re all transported. And then all of a sudden, you have a community around it. And then other bands start because they see that there’s this opportunity, there’s this place. There’s a strategy for living. It isn’t what you’ve been sold. And so, you know, I reject it. I fucking reject it in rock and roll. The radical, individuated self-expression of rock and roll and the self-liberation of it — that’s all that matters.” He makes it sound so simple. What if it is?" Source: insidehook.com

At first Donnie/the antihero has an impulse to harm others, and then he turns it inward and imagines an elaborate scenario by which he "saves" people. His destructive, lashing-out impulse has found a personal mythology that makes him feel justified and good. Catcher in the Rye's Holden character has a fantasy of saving children running through a field toward a cliff. Holden Caulfield is the guy who catches them before they fall to their deaths. By the end of that novel, we realize Holden is in therapy and undeniably suicidal. His rejection of "phonies" is very similar to Donnie Darko's hostility toward the moral preachings of those at the high school. By burning down the house of the Patrick Swayze's pedophile character, Donnie Darko basically "catches" the Sparkle Motion girls (and his little sister) by preventing the local creep from getting to them.

The fear/love dichotomy is similar. He fears dying, especially the loneliness of dying by his own hand, fears many other things, especially losing his girlfriend Gretchen and his family. He wants to love and be loved. His parents are shown to be very loving people, but not reaching him, not even his doting mother. He really doesn't want to hurt them. He finds a way to think that if he dies, he is somehow doing them a favor. Part of him realizes that the fear/love dichotomy is a cop-out, so by the end he has accepted that if it has to be one concept winning above the other, it should be love. 

The arrow of time, and the blob that goes in front of people before they take action, is like what he sees himself moving toward. But he's schizoprenic and starts to see his decision as inevitable. He goes onto a kind of autopilot toward his oblivion. That is similar to the resignation and elation that many suicidal people have just before they commit the deed. Often it is a sense of peace after the decision has been fully finalized and accepted. In suicidal research literature, this is often the time when people are giving away their personal items, as they don't care any more about possessions. Donnie's parents give him a lot of "new stuff" as a reaction to him getting in trouble at school, and unfortunately it doesn't mean much to him.

One major element of the story is the idea of destruction being a part of creation. "The Destructors" by Graham Greene is about young people destroying a man's wealth and home, and the story is said to mean something about destruction being a positive thing. It is the young reclaiming something from the old, an expression of vitality and renewal. I think the fixation on this story is completely a part of the psychological process Donnie Darko is working out. Interestingly, the term "cellar door" represents a portal to a downward location -- a portal one passes through to death. It's also a term from "a famous linguist," whom the screenplay avoids mentioning was J.R.R. Tolkien, whose claim to fame was the creation of a vast fantasy realm and mythology. Donnie Darko is creating his own personal mythology as he moves toward the "cellar door" of his demise. The two words are cast as "the most beautiful in the English language": death recast as a high form of beauty. Suicidal ideation.

Basically, Donnie considers himself a liability to his community. He falls in love with the new girl at school, but he imagines he might end up losing her, and fantasizes finally with saving her life. His therapist isn't making any real progress with him and recurs to use placebo medicine. The echo-voiced bunnyman he imagines doesn't seem to be alive -- it is a half-dead bunny face, like a skull. A bunny is a symbol of innocence but in the form Donnie hallucinates, it becomes a symbol of innocence turning to death, of something that has become rotten in its springtime. That's how he feels on the inside: Like he's not youthful or vital or hopeful like he thinks he ought to be, but already dead inside.

On October 2, 1988, Donnie Darko — a euphemistic “troubled teen” — receives a dreamlike message from a satanic bunny named Frank, that the world will be ending on October 30. Donnie accepts this news fairly stoically, but it’s just the beginning of a month of nightmares about destruction that Donnie then re-creates in real life. Or does he? Is anything that happens between the warning to Donnie of impending apocalypse and the date of its predicted arrival real? Is it all a drug-induced hallucination? Or a psychosis-induced fantasy, a detachment from reality? Donnie Darko is what Ferris Bueller’s Day Off might have been if David Lynch had ever gotten his hands on it, a daring, disturbing, visionary debut from writer/director Richard Kelly. 

It's at times a bleak and pessimistic vision, but it reflects some of the feelings of Xers that they’ve been ignored and unappreciated. Donnie knows where his parents hide their gun. The inevitable chest-blob-arrow leads him right to it, as though it's not even his own decision anymore. He imagines a scenario where he'll end up using the gun on somebody else, out of revenge or some angry impulse. He doesn't want to do that. Up close, the gun's barrel is a wormhole of time. The bullet's aim is the arrow of time. The bullet is the jet engine. The Philosophy of Time Travel becomes the ability to make time stop, for him and him only. Source: popmatters.com