The defence of "non-insane automatism" is a defence available at common law.
The law treats "almost all automatisms as the product of a mental disorder leading…to an NCR-MD verdict."
- Automatism Defined
Automatism is "a state of impaired consciousness". This is in contrast with "unconsciousness, in which an individual, though capable of action, has no voluntary control over that action". The person engages in "involuntary behaviour" such that "a person who, though capable of action, is not conscious of what he is doing. It means an unconscious involuntary act where the mind does not go with what is being done." 
The term "automatism" refers to the involuntary conduct that is the "product of a mental state in which the conscious mind is disassociated from the part of the mind that controls action". Accordingly, automatism relates only to the actus reus of the offence as it affects the voluntariness of the accused's actions.
- Effect of Finding
There are two types of automatism. There is mental disorder automatism and there is non-mental disorder automatism. The finding of the former leads to an Not Criminally Responsible finding. The latter leads to an acquittal.
An NCR verdict permits a "post-verdict dangerousness assessment of the accused" that allows the court to tailor disposition to the specifics of the case.
- R v Luedecke, 2008 ONCA 716 (CanLII), per Doherty JA - overturning a verdict of non-insane automatism
- R v Stone, 1999 CanLII 688 (SCC),  2 SCR 290, per Bastarache J, at para 156
- R v Rabey, 1977 CanLII 48 (ON CA), (1977) 37 CCC (2d) 461 at 155, per Martin JA at 156
R v SH, 2014 ONCA 303 (CanLII), per Watt JA, at para 63
R v Luedecke, 2008 ONCA 716 (CanLII), per Doherty JA, at para 54
SH, supra, at para 63
R v Alexander, 2015 BCCA 484 (CanLII), per Stromberg-Stein JA at para 28 ("A defence of automatism amounts to a denial of the voluntariness component of the actus reus of the offence. A person who is unable to control whether to perform an act, or how to perform an act, cannot be said to have committed the act voluntarily. Conduct which is not voluntary cannot be criminal.")
Alexander, ibid., at para 29
- Luedecke, supra
Burden and Standard of Proof
The burden is on the accused to prove involuntariness on a balance of probabilities.
The accused has the evidentary burden to adduce evidence to raise the issue for the court and the legal burden of proving the fact alleged.
The defence must provide confirming psychiatric evidence. It must establish more than the claim that involuntariness is "plausible".
- R v Stone, 1999 CanLII 688 (SCC),  2 SCR 290, per Bastarache J at para 171, 179 (“The foregoing leads me to the conclusion that the legal burden in cases involving claims of automatism must be on the defence to prove involuntariness on a balance of probabilities to the trier of fact.”)
R v SH, 2014 ONCA 303 (CanLII), per Watt JA, at para 65
Stone, supra at paras 173, 182
Stone at p. 187
R v Enns, 2016 ONSC 2229 (CanLII), per Fregeau J, at para 20
In order to establish automatism it is necessary for the defence to 1) claim that he acted involunarty and 2) adduce expert evidence to support the involuntariness claim.
The judge must then take a two-step inquiry. First, the judge must "determine whether the accused person has established a proper evidentiary foundation for a defence of automatism".Second, the judge must determine which form of automatism should be left with the trier of fact".
- evidence of a documented medical history of automatistic-like dissociative states;
- evidence of a bystander about the appearance of the accused before, during and after the alleged involuntary conduct (para 190); and
- evidence of motive or absence of motive
Legal Character of Automatism (Mental Disorder vs Non-Mental Disorder)
Where the evidentiary burden has been made out to the satisfaction of the trier of fact, the judge must make a determination of the legal characterization of automatism. That is, the judge must then determine "whether mental disorder or non-mental disorder automatism should be left with the trier-of-fact".
In a jury trial, the judge must decide whether automatism should be put to the jury.
The analysis should begin from the premise that automatism originates from a mental disorder..
- internal cause factor;
- continuing danger factor; and
- other policy concerns.
It is only in the "rare" cases that the form of automatism will be a non-mental disorder in nature. The form of non-mental disorder automatism will usually occur when all the following are true:
- the accused suffered a single incident of automatism;
- it was triggered by a specific external event;
- the trigger is unlikely to reoccur; and
- the vent could have caused a dissociative state in a normal person.
The question of which form of automatism is available is a question of law and so can only be decided by the judge.
- R v SH, 2014 ONCA 303 (CanLII), per Watt JA, at para 72
R v Enns, 2016 ONSC 2229 (CanLII), per Fregeau J, at para 21
Stone at p. 193
- SH, supra, at para 72
- SH, supra, at para 73
- SH, supra, at para 73
- SH, supra, at para 74
R v Alexander, 2015 BCCA 484 (CanLII), per Stromberg-Stein JA at para 36 to 38
- Alexander, supra, at para 38
Stone, supra at para 203
Stone, supra, at para 199
Alexander, supra, at para 36
- Alexander, supra, at para 37
Luedecke, supra, at para 63
Alexander, supra at para 32 to 33