REM behavior disorder (RBD) is a condition where the normal paralysis that occurs during REM sleep doesn’t take place. People with REM behavior disorder can move during this sleep phase, and often act out physically in reaction to their dreams. This activity can be violent—thrashing, kicking, getting out of bed—and can lead to injury to the sleeper or a bed partner. We don’t know precisely what causes RBD, but it is associated with neurological illness and injury, as well as to withdrawal from alcohol or narcotics, or use of some anti-depressants.
Nightmares and disturbed dreaming are a hallmark of post-traumatic stress disorder (PTSD), as is disrupted sleep. People who suffer from PTSD often experience frequent and recurring nightmares, which may be accompanied by acting out during dreams, with symptoms similar to REM behavior disorder. PTSD occurs in some people who’ve experienced forms of trauma, including assault, disaster, war and combat. Soldiers who’ve served in active combat often experience sleep problems and disordered dreaming linked to trauma and PTSD. After years of observing a particular group of symptoms among combat soldiers, sleep scientists are now proposing the creation of a new sleep disorder: Trauma Associated Sleep Disorder, with symptoms that include nightmares, sleepwalking and other disruptive nighttime behaviors.