Under the law an accused person cannot be convicted of a criminal offence unless it can be proven beyond reasonable doubt that when the crime was committed the actions of the offence were subject to control and will. There is a presumption of mental capacity and that the accused acted to an exercise of will however this presumption can be displaced if there is evidence to the fact.
There are three ways that an act can be considered to be involuntary (at law).
- When criminal act caused by reflex action; or
- When conduct was performed whilst the accused was in a state of impaired consciousness
The defence of automatism is used to refer to involuntary conduct in the third sense of being performed in a state of impaired consciousness. The term automatism implies to total rather than partial absence of control and direction of will.
There are various conditions that give rise to automatism they include:
- concussion from blow to the head
- sleep disorders
- consumption of alcohol or other drugs
- neurological disorders
- dissociation arising from extraordinary external stress
It is important to note that there is a difference between automatism and mental impairment. The focus when using the defence of automatism will be where or not the conduct was involuntary as a result of that condition, therefore depriving the accused of the will to act.