I hope you find these resources helpful. They're just ideas for starting points. Your research may lead you to better sources. Please ask for help if you aren't finding what you need.
"Was He Crazy..." is a review of Into the Wild that was published in PsycCritiques, a publication of the American Psychological Association. This article is a fantastic starting point for your research. It will give you lots of ideas for ways to think of Chris McCandless. Was he:
This is, imho, a great article from a very reputable source, but don't let this article influence you too much! Remember that the author is just working from the book and the film. It's not as if she was McCandless's therapist. If you agree or disagree with the author, find more information so you can make a compelling argument in your paper.
You'll find suggested resources for researching some of the above questions on this page.
Also be sure to take a look at the articles discussed in the box below this one.
You can find literary criticism on Into the Wild in vol. 248 of Contemporary Literary Criticism. This set is located in the reference area. We've scanned much of it and created a link below. For info on how to cite these sources, look in the front of the most recent volume of Contemporary Literary Criticism (ask a librarian for help).
I Now Walk Into the Wild is an excellent article published in The New Yorker.
Another possible direction for your paper would be that McCandless wanted to experience an extended period of solitude, not unlike his hero, Thoreau.
One direction you could take with your paper would be to argue that McCandless was immature; that he behaved like a typical teenager in his risk-taking, rebellion, and inability to contemplate his own mortality. You can find info on risk taking and rebelliousness elsewhere on this page. For info on the inability of teens to contemplate mortality, take a look at chapter 17 of this book.