Automatism

Automatism is an excuse defense against criminal liability for defendants who committed a presumptively criminal act in a state of unconsciousness, semiconsciousness, or unawareness. Medically, the term automatism refers to motor behavior that is automatic, undirected, and not consciously controlled. The use of automatism as a legal defense is relatively rare and is typically claimed in cases where the defendant’s conscious awareness is compromised by epilepsy, brain injury, somnambulism (sleepwalking), or trauma. The automatism defense is recognized as a viable defense in U.S. and British courts, but the definitions and applications of the defense vary widely and are often inconsistent. The basis for the defense is that a defendant should not be held responsible for presumptively criminal actions because of the involuntary nature of the behaviors, leading to lack of criminal intent and voluntary criminal action.