It's entirely up to you what, if any, connection you draw between this movie and mental illness. Fallen is a movie with the great actor Denzel Washington. The movie is about a demon named Azazel. Azazel has been alive for thousands of years. These demons used to be angels that were in league with Satan and attempted to overthrow God.

God punished them by casting them out of heaven and depriving them of form. The only way they can exist is to inhabit the bodies of people. A demon takes over a person's body and reapes havoc kiling as many people as it can and then taking the life of that person.

Once the person is dead, the demon simply moves on to another and its “wash, rinse, repeat” until the entire human race is decimated.

In the movie, many people that would not ordinarily do or say anything even close to bad, suddenly become sadistic murders when taken over by Azazel. This devastation on the human race is the demon's vengeance for being cast out of heaven.

There are those that believe that Mental Health is the result of demon possession. The reason then why a person that is mentally ill cannot remember what they are accused of doing is because the demon has left them.

Another theory is that mental illness is an “after effect” of demon possession that was passed down from previous generations. Whether you ascribe to any of these theories, Fallen is a very good movie that will leave you wondering if there are puppet masters behind the scenes pulling the strings and running the show.