APA Dictionary of Psychology

a parasomnia characterized by the loss of the normal muscle atonia that occurs during rapid eye movement (REM) sleep, resulting in dream enactment behaviors such as talking, shouting, punching, kicking, or other complex movements. These behaviors often reflect vivid or intense dreams and may lead to sleep disruption or injury to the affected individual or a partner. RBD may occur idiopathically or in association with neurological conditions, particularly synuclein-related neurodegenerative disorders such as Parkinson’s disease, dementia with Lewy bodies, and multiple system atrophy. It has also been observed in some individuals with narcolepsy, obstructive sleep apnea, or those taking certain medications, including some antidepressants. Growing evidence suggests that, in some cases, RBD can precede the onset of neurodegenerative disease by years, making clinical evaluation and monitoring important. Also called REM behavior disorder (RBD).