If they've been happening for five years, I'd say that now is probably a good time to try and get rid of them. Lucid dreaming can help with that, not only with you recognizing when you're dreaming, but also getting you thinking about what might be causing these.

Typically, what kinds of movies do you watch? What books do you read? What video games do you play? What do you and your friends talk about? Are you easily angered? Do you tend to hold grudges against others? How do you feel about these dreams when you wake up (angry, scared, apathetic, annoyed, etc.)? Have you ever tried getting them to go away? Is there any reason you can think of that these dreams are appearing?