Could REM Sleep Behavior Disorder Kill You in Your Sleep?

Written by Adam Rothman with contributions by Kevin Morton, Winter 2010

REM sleep behavior disorder (or RBD) is truly one of the most intriguing, and indeed troublesome, sleep disorders known to man.

In essence, it causes the afflicted individual to act out their dreams to some extent. Can you imagine that?! Thinking about some of the dreams I’ve had, I know I could seriously harm myself or others if I ever unknowingly acted them out, even if in my room.

And indeed, REM behavior disorder has led to some gut-wrenchingly tragic tales. Extreme cases where RBD afflicted individual have unwittingly murdered truly loved spouses lying next to them in bed have caused some of the most intense grief. With the help of sleep experts, the court cases that follow these events have become incredibly intricate and complex, and in some cases the defendants have been acquitted. (Learn about some of these cases, and other incidences of violence during sleep.)

To understand how REM sleep behavior disorder works, you have to understand one characteristic mechanism of REM sleep. To do this, we’ll start with a short hypothetical story.

ou go to sleep one night, exhausted from the day’s activities. Over the course of the next few hours you have an incredibly vivid dream in which you walk, run, and jump all around your home. Even though you’re asleep, your brain is wide awake and experiencing these activities. Every movement you make in-dream is accompanied by an equivalent instruction from your brain to the appropriate body part. And yet, when most people awaken the following morning, they remain safely in their beds. So what keeps them there?

The REM (rapid eye movement) phase of sleep is the most active time of night for the brain. Unsurprisingly, this is also the phase of sleep during which most vivid dreams occur.

During normal REM sleep, certain parts of the body experience muscular atonia: a temporary paralysis. This atonia prevents the instructions sent by the brain from being carried out by the body. In other words, you have atonia to thank every time you wake up exactly where you fell asleep.

REM sleep behavior disorder is characterized by the occasional failure of this atonia. The brains of patients who suffer from REM sleep behavior disorder have complete control over their sleeping bodies, allowing (often exaggerated) motor activity to occur in relation to what is happening in the dream.

The loss of paralysis can result in movement ranging from minor twitching to thrashing and/or leaping. In the most extreme cases, REM behavior disorder patients have been known to act out entire dreams. As alluded to when we mentioned the tragic deaths above, if the dream is violent in subject matter, the patient’s actions can be harmful to him/her or those around him/her.

The severity of REM behavior disorder is determined based on the frequency of episodes and their duration, completeness, and tendency towards violence. Frequencies range from once every few weeks to multiple episodes per night. Episodes are typically between two and ten minutes in length.

RBD is caused by a dysfunction of the brain stem mechanisms responsible for the normal suppression of muscle tone and paralysis in REM sleep. The condition is most prevalent in men over the age of fifty (though it has been observed in both men and women of all ages). It remains unknown why the condition appears to preferentially affect males. In all patients, the condition is chronic and progressive.

Fortunately, RBD is highly treatable with a variety of medications. Clonazepam, an anticonvulsant, muscle relaxant, and anxiolytic, is the most common prescription (1-2 mg at bedtime). Because episodes can occasionally overcome medication, dangerous objects should be removed from the patient’s room and appropriate measures should be taken to ensure the safety of the patient and his/her sleeping partner.