We all have violent or terrifying dreams on occasion, but for most of us, the action stays in the dream. However, for people with REM sleep behavior disorder, or RBD, the action in the dream is acted out in reality!
Normally when you dream your body can’t get up and actually do the things that are happening in the dream, but RBD allows the body to do exactly that, which can be dangerous. People with RBD have been known to injure themselves and others by punching, kicking, and bumping into things.
Scientists have found that people with RBD tend to have more violent dreams than other people. They think that the cause of RBD is a problem with the brain stem. The brain stem is very primitive, and may be involved with how and why we dream.
Why do people with RBD have so many violent dreams?
Good question. One theory suggests that dreams evolved as a way to confront threatening situations and learn to handle them. Early in human evolution, one of the most common threats was attack by wild animals, so perhaps people with RBD are more closely in touch with dreaming in its more primitive stages.