The Law Related to Automatism

Posted: May 31, 2023
By: The Law Firm of Ted Yoannou


What is Automatism?

At common law, automatism is “a state of impaired consciousness, rather than unconsciousness, in which an individual, though capable of action, has no voluntary control over that action.”[1] To secure a conviction, the Crown must prove beyond a reasonable doubt not only that the criminal act was committed, but also that it was done voluntarily. Since a defendant could not have acted voluntarily while in an automatistic state, automatism acts as a full defence to criminal charges. [2]

Types of Automatism

Automatism has two subtypes with different legal outcomes. The first is non-mental disorder automatism [NMDA], which results from a cause that could leave the average person in an automatistic state.[3] Common examples are concussions or an extreme shock, such as witnessing a traumatic event. The second category is mental disorder automatism [MDA], which results from a “disease of mind.”[4] This is a much more flexible category than diagnosable mental disorders; MDA can be caused by any vulnerability specific to the defendant that made them particularly susceptible to a given trigger (or triggers).[5]

Whereas NMDA results in an unqualified acquittal, MDA leads to a finding that the defendant is not criminally responsible.[6] A not criminally responsible verdict results in a qualified acquittal which may have additional conditions attached. In these cases, the court provides a tailored disposition based on a “post-verdict dangerousness assessment” of the risk the defendant could pose to the public.[7] Although this makes a finding of NMDA more desirable, Judges start from a presumption of MDA and successful cases of NMDA are rare .[8]

Establishing a Successful Defence

For an automatism defence to succeed, the defence must show on a balance of probabilities (that it is more likely than not) that the defendant was acting involuntarily.[9] Expert psychiatric or psychological evidence is necessary in every case to establish the defence, but it usually requires additional evidence. The courts have recognized three types of evidence that are particularly relevant, but other evidence may also be applicable.[10]

Firstly, a documented medical history of automatistic-like dissociative states lends additional weight to expert testimony.[11] As such, most successful automatism defences involve documented medical conditions associated with dissociative states (e.g., epilepsy, PTSD, or a concussion).[12] However, automatism can be successfully made out without this type of evidence.[13]

Second, bystander evidence about the defendant’s appearance before, during, and after the alleged involuntary conduct helps corroborate the defence.[14] Key indicators of automatism include glassy eyes, unresponsiveness, and appearing distant or “spacey.”[15]

Finally, evidence of whether the act would have been committed without the automatistic state may undermine alternative explanations.[16] A lack of discernable motive for the act casts doubt on the theory that the defendant would have committed the act voluntarily.

Extreme Intoxication Akin to Automatism

A special category of NMDA is extreme intoxication akin to automatism, where the defendant is acting involuntarily because they are intoxicated. Unlike other forms of automatism, it is subject to three caveats.

Firstly, alcohol consumption alone is likley insufficient to support a finding of automatism. Although the Supreme Court has declined to explicitly foreclose a finding of extreme intoxication akin to automatism for alcohol alone, it has also stated that “it is not clear that extreme alcohol intoxication causes NMDA as a matter of basic science.”[17] The courts may also be apprehensive to allow a defense based solely on alcohol intoxication for policy reasons. As such, expert testimony supporting automatism caused by alcohol intoxication alone would face heavy scrutiny.

Second, extreme intoxication akin to automatism caused by voluntary intoxication cannot be a defence for violent crimes where the Crown can show that the defendant acted negligently by consuming the intoxicating substance(s) while knowing that their extreme intoxication could lead them to harm other people.[18]

Finally, extreme intoxication akin to automatism caused by voluntary intoxication cannot be used as a defence for impaired driving charges in Ontario.[19]


**This article was provided by law student Jason Ruggeberg. It is intended for general information purposes only, and not as specific legal advice.**


[1] R. v. Stone, 1999 CanLII 688 (SCC), [1999] 2 SCR 290, <> at para 156 [Stone]

[2] Ibid at para 169-170

[3] Ibid at para 207

[4] Ibid at para 195; R. v. Luedecke, 2008 ONCA 716 (CanLII), <> at para 84[Luedecke]

[5] Stone, supra note 1 at para 195; R. v. S.H., 2014 ONCA 303 (CanLII), <> at para 75-80 [S.H.]

[6] Stone, supra note 1 at para 194; Luedecke, supra note 3 at para 84

[7] Stone, supra note 1 at para 194, Luedecke, supra note 4 at para 6, 101

[8] Stone, supra note 1 at para 199, 203; R. v. Alexander, 2015 BCCA 484 (CanLII), <> at para 38

[9] Stone, supra note 1 at para 171, 179; S.H., supra note 5 at para 65

[10] Stone, supra note 1 at para 189-192; S.H. supra note 5 at para 71

[11] Stone, supra note 1 at para 189-191; S.H., supra note 5 at para 70-71

[12] Stone, supra note 1 at para 186; see also R. v. Courneyea, 2013 CMAC 3 (CanLII), 7 CMAR 714, <>; R. v. Taylor, 2008 CarswellOnt 1331, [2008] O.J. No. 946, 64 M.V.R. (5th) 109, 78 W.C.B. (2d) 212; R. v. Farrington, 2013 ONCJ 235 (CanLII), <>

[13] R v Prescott, 2008 ONCJ 604

[14] Stone, supra note 1 at para 189-191; S.H., supra note 5 at para 70-71

[15] Stone, supra note 1 at para 189-191; R v Desrosiers, 2017 ONCJ 299 at para 14-16

[16] Stone, supra note 1 at para 189-191; S.H., supra note 5 at para 70-71

[18] Criminal Code, R.S.C., 1985, c. C-46, s 33.1

[19] R. v. Abad, 2009 CarswellOnt 3453, [2009] O.J. No. 2515, 83 W.C.B. (2d) 613, 86 M.V.R. (5th) 54 at para 115-118; R. v. Penno, 1990 CarswellOnt 115, 1990 CarswellOnt 1003, [1990] 2 S.C.R. 865, [1990] S.C.J. No. 96, 115 N.R. 249, 11 W.C.B. (2d) 200, 29 M.V.R. (2d) 161, 42 O.A.C. 271, 49 C.R.R. 50, 59 C.C.C. (3d) 344, 80 C.R. (3d) 97, J.E. 90-1423, EYB 1990-67564 at para 67

This article has been prepared for our website for general information purposes only and is not intended as legal advice. Please Contact Us if you wish to review the particular circumstances of your case
Posted under DUI, Driving Offences, Impaired Driving
Go back to the Article Archive

Call (705) 302‑0468 or Fill Out Our Quickform Below. Prompt Reply Guaranteed.