The study found 39-41 clinical cases of RBD associated with potentially lethal behaviors against self and/or others that involved a child and adults of all ages. The relevant behaviors documented were choking/headlock (22-24 incidents), running through a second-floor window (1 case of a child with RBD), and diving from a bed (10 incidents). The study concludes that vigorous RBD behaviors may lead to the same potentially lethal consequences to the patient or bed partner as would violent behaviors, because of "victim vulnerability" factors that can increase the risk for major morbidity or morality. A "spectrum of vulnerability" can be developed for RBD that can predict the degree of vigor and violence of the RBD behavior. This paper outlines criteria for determining whether a violent incident that results in harm to self or others is related to a RBD incident. First, there should be reason, by history and/or formal evaluation, to suspect RBD. Second, the duration of the action is usually brief (seconds to minutes). Third, the behaviors are usually confined to the bed or the bedroom. Fourth, the behavior is usually abrupt, immediate, impulsive, and senseless. Fifth, the victim is someone who merely happens to be present (e.g., the bed partner), and who may also have inadvertently instigated or escalated RBD violent behaviors through reflexive defensive actions. Sixth, immediately upon awakening, there is perplexity or horror, without attempt to escape, conceal, cover-up, or rationalize the action. Seventh, there is amnesia for the event (but not the dream). Eighth, polysomnographic evaluation reveals REM sleep without atonia as a persistent abnormality. 1 figure, 1 table, and 112 references