One of the simplest, and most prevalent theories behind Donnie Darko is explained by the fact that Donnie could simply be suffering from schizophrenia. The poorly understood mental illness is often used as a crutch by screenwriters to spice up their films. According to CBC, schizophrenia is often misrepresented in TV and film, and Donnie Darko was even specifically called out when the report read, " Another common representation of schizophrenia makes the condition out to be supernatural or magical, like in...the film Donnie Darko...it diminishes the real-life experience of living with schizophrenia and suggests that it is beyond humanity or our understanding". Or, to put it another way, everything that happens to Donnie in the movie is manipulating him to the point where he will save the Primary Universe, even though it will lead to his own death there. Thank you to all the fans who've come up to me over the years with that confused look on their faces and asked me: 'What the f**k is Donnie Darko about??'" The tangent universe is certainly the first chapter from the prologue of The Philosophy of Time Travel," he said to NME, "so I believe there's a lot more to that book than meets the eye."

Seeing a vortex has formed over his house, Donnie drives to the edge of town, and watches as a plane gets caught in it and one of the engines is ripped away. The last 28 days rewind, and Donnie wakes up in his bedroom just as the jet engine falls from the sky.Is it a teen movie, a 1980s period piece, a musing on life and death – or a sci-fi film about time-travel? Writer/director Richard Kelly, who was just 25 years old when he made the movie, prefers audiences to decide, but he did tell the Los Angeles Times in 2001: "I wanted to write a film that pushed the envelope by combining science fiction with a coming-of-age tale." Director Richard Kelly also spoke about the meaning of Donnie Darko ( via NME), and he admitted that most of the fan theories are all wrong. However, he was also coy in the interview about many of the questions concerning Donnie Darko's ending. He avoided the idea that Donnie was dead all along, saying that life and death can co-exist. He did say Donnie wasn't hallucinating and everything in the movie is real "to a certain extent." Finally, he said "life could be a dream" and Roberta Sparrow was onto something with Philosophy of Time Travel. Of course, it is most likely that the tangent universe theory is the one he had in mind when he made the movie, and Kelly hints that it is worth considering when you revisit Donnie Darko.

Well, not exactly – when the Director's Cut was released in 2016, not everyone was thrilled with the news that the mysteries of Donnie Darko had been solved. Kelly, however, refuses to confirm that Director's Cut version is the only way to interpret his film – it is just one way to enjoy it. In his interview with the NME at the time of its release, he teased other theories, including Donnie's adventures being a hallucination, by saying: "I don't have an absolute definition of hallucination, I believe everything in the film is real to a certain extent, but what is the nature of reality?" In an interview with Coming Soon, he talked about the possibility of a follow-up, saying: "I'm probably not allowed to say anything more than there has been an enormous amount of work completed. I'm hopeful that we might get to explore that world in a very big and exciting way. But we'll see what happens. But there has been a lot of work done." In fact, they prevent the film from being a text that the viewer could read into whatever they wanted… in this version of the film, you are almost forced to put very specific pieces into a singular puzzle. And it feels less magical as a result."While many people are as confused as Jake by a plot that also features a budding romance for Donnie, his younger sister's performance of Duran Duran's ‘Notorious’ with the Sparkle Motion dance troupe, and the revelation that Cunningham has a hoard of child porn in a secret room at his house – there are a handful of theories about what it all means. In the last two decades, it has become much more than that. While Donnie Darko started life as a box-office flop (partly because it was released just after 9/11 in the US, when no-one was going to cinemas), it later became a word-of-mouth hit on DVD and at midnight screenings. It is now regarded as a cult classic – and one that still has viewers debating the ending – and discussing it at length online. Cult movie Donnie Darko was released 22 years ago – and fans are still debating what the enjoyably head-scratching, Jake Gyllenhaal-starring drama is all about.

I wrote [Roberta's] time travel book," Kelly revealed to Horror Cult Films in 2016 when the Director's Cut came out. "I'm not the kind of person who puts something like that in a movie without figuring out what's inside it. I had to figure it out," he explained.For example, rabbit Frank persuades him to flood the school, which leads to Donnie bumping into Gretchen on the way home. They become a couple, and her death soon after causes him to shoot the man responsible – a man named Frank who has a rabbit costume because it is Halloween – thus creating Frank, the manipulated dead man. Donnie then realises he can 'save' Gretchen by sending the jet engine though a vortex, rewinding time and erasing the history that led to her death.