RBD is a parasomnia in which people act out their dreams. The major feature of RBD is loss of muscle atonia (i.e., the loss of paralysis) during REM sleep. REM sleep is the stage of sleep in which most vivid dreaming occurs. The loss of motor inhibition leads to a wide spectrum of behavioral release during sleep. This extends from simple limb twitches to more complex integrated movement. These behaviors can be violent in nature and in some cases will result in injury to either the individual or their bedmates. RBD is categorized as either idiopathic or symptomatic. Idiopathic RBD is the term used when RBD is not associated with another neurological condition. Up to almost 90% of patients with idiopathic RBD will go on to develop a neurodegenerative disorder. The disorders most strongly associated with RBD are the synucleinopathies, particularly Parkinson's disease, dementia with Lewy bodies, and to a lesser extent, multiple system atrophy. When it results from an identifiable underlying etiology, RBD is referred to as symptomatic RBD. Medications known to exacerbate RBD, including serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, and tricyclic antidepressants, should be discontinued or avoided. In-laboratory video PSG is necessary for a definitive diagnosis of RBD. Even when abnormal behavior does not occur during the study, REM sleep without atonia (RSWA) is characteristically present and required for the diagnosis. Establishing a safe sleeping environment is the primary goal of treatment. Clonazepam and Melatonin are the most frequently used for RBD treatment (even when the underlying synucleinopathies are not).