January 2021 | Reviewed by: Andrea Matsumura, MD
What is REM Sleep Behavior Disorder?
REM sleep behavior disorder (RBD) is a parasomnia. A parasomnia involves undesired events that happen while sleeping.
RBD occurs when you act out vivid dreams as you sleep. These dreams are often filled with action. They may even be violent. Episodes tend to get worse over time. Early episodes may involve mild activity. Later episodes can be more violent. RBD is often ignored for years. At some point, it is likely to result in an injury. Either the person dreaming or the bed partner may be hurt.
RBD can be confused with sleepwalking and sleep terrors. In these other disorders, you are usually confused upon waking up and there is no dream reenactment. You do not become rapidly alert. In contrast, it is normally easy to wake a person with RBD who is acting out a dream. Once awake, you are also able to recall clear details of the vivid dream.
The details of this dream match the unusual behavior of an RBD episode. These actions may include any of the following:
For example, a man with RBD may dream of playing in a game of football. In this case, he might dive from his bed to catch the winning touchdown pass. He might also dream of being chased by an attacker. This may cause him to leap out of bed to run away.
People with RBD rarely walk, have their eyes open, or leave the room. These are all common signs of sleepwalking. RBD episodes do not involve eating or drinking. They also do not involve sexual activity or going to the bathroom.
RBD episodes occur during REM sleep. Normal sleep consists of a series of REM dream episodes. They occur about every 1.5 to 2 hours each night. This means that an RBD episode tends to first appear at least 1.5 hours after falling asleep. Episodes may continue to occur until waking up in the morning. Active RBD episodes may appear as many as four times per night. They may also occur as rarely as once per week or per month. RBD does not normally appear during a nap.
RBD by itself does not cause the dreamer to be sleepy during the day. But it is often found along with other sleep disorders. These disorders may cause daytime sleepiness. Examples of these disorders include the following:
An RBD episode often disrupts the sleep of a bed partner. This is how a person with RBD may become aware of the problem. RBD is a medical problem. It is not a psychiatric disorder. People with RBD do not normally have a mental problem.