R. v. S.H., 2014 ONCA 303:
(1) The Nature of Automatism
 Automatism is a state of impaired consciousness in which a person, though capable of action, has no voluntary control over that action: Stone, at para.156. The term "automatism" has been held to refer to 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: Luedecke, at para. 54.
 Automatism relates to the actus reus or external circumstances of an offence. To be more specific, automatism has to do with the voluntariness component of the actus reus. The requirement of voluntariness is fundamental to the imposition of criminal liability and reflects our underlying respect for an individual's autonomy. The voluntariness requirement also reflects the principle that unless a person has the capacity and a fair opportunity to adjust his or her behaviour to the law, its penalties ought not to be applied to him or her:Luedecke, at para. 56.
 The law presumes that people, including those charged with crime, act voluntarily: Stone, at para. 171. The presumption is rebuttable. Automatism amounts to a claim that the conduct of a person charged with crime was not voluntary. It follows that a person charged who invokes automatism in answer to the charge bears the burden of rebutting the presumption of voluntariness:Stone, at para. 171.
(2) The Burden and Standard of Proof on Automatism
 The term "burden of proof" is used in two senses. The first, often described as the "evidentiary burden", refers to the obligation of a party to adduce evidence sufficient to warrant consideration of an issue by the trier of fact. The second, referred to as the "legal burden" or "persuasive burden", describes the obligation of a party to prove or disprove the fact at issue. Both apply to claims of automatism. As a matter of general principle, the legal burden follows the evidentiary burden. This is so for automatism: Stone, at paras. 173 and 182.
 Where automatism is advanced in answer to a charge, the evidentiary and legal burdens of proof settle on the person charged.
 To satisfy the evidentiary burden, an accused must adduce evidence upon the basis of which a properly instructed jury could find, on a balance of probabilities, that his or her conduct was involuntary: Stone, at para. 182.
 To meet the legal burden, an accused must satisfy the trier of fact, on a balance of probabilities, that his or her conduct was involuntary: Stone, at para. 179.
(3) Discharging the Burden of Proof
 To satisfy the evidentiary burden in automatism cases, in other words, to put the claim of automatism in play, an accused must
i. claim that she or he acted involuntarily; and
ii. adduce expert evidence to support the involuntariness claim.
Stone, at paras. 183-184.
 The court in Stone makes it clear that a mere assertion of involuntariness will not be enough to meet the evidentiary burden: Stone, at para. 183. The claim must be confirmed by expert evidence, sometimes described as "psychiatric evidence" (para. 184), and on other occasions as "expert psychiatric or psychological evidence" (para. 192).
 The Stone majority offered some guidance about the nature of the additional evidence that may be relevant for consideration in deciding whether an accused had satisfied the evidentiary burden to put automatism in play before the trier of fact. That evidence includes, but is not limited to:
i. evidence of a documented medical history of automatistic-like dissociative states (para. 189);
ii. evidence of a bystander about the appearance of the accused before, during and after the alleged involuntary conduct (para. 190); and
iii. evidence of motive or absence of motive (para. 191).
 Where an accused has satisfied the evidentiary burden in connection with automatism, it falls to the trial judge to determine the legal characterization of the automatism. In a jury trial, the trial judge must decide whether mental disorder automatism or non-mental disorder automatism should be left to the jury. In judge alone trials, the distinction between the evidentiary and persuasive burden tends to become blurred since the judge is both the trier of law and the trier of fact. Irrespective of the mode of trial, however, the trier of fact will decide whether the accused has satisfied the legal or persuasive burden of proof.
(4) The Legal Character of Automatism
 The criminal law characterizes automatism as mental disorder automatism or non-mental disorder automatism. What distinguishes one characterization of automatism from the other is the presence, in the former, and absence, from the latter of a "mental disorder" as defined in s. 2 of the Criminal Code. The assessment of which form of automatism should be left to or considered by the trier of fact comes down to whether the condition alleged is a mental disorder:Stone, at para. 193.
 Despite the presumption in s.16(2) of the Criminal Code that every person is presumed not to suffer from a mental disorder so as to be exempt from criminal responsibility under s. 16(1) of the Criminal Code, we are to begin from the premise that automatism originates in a mental disorder and then examine the evidence to determine whether the condition does not originate in a disease of the mind: Stone, at para. 199; and Luedecke, at para. 90.
(5) What Constitutes a "Mental Disorder"
 Section 2 of the Criminal Code exhaustively defines the term "mental disorder" as it is used in the Criminal Code. A mental disorder is a disease of the mind. Mental disorder is a legal term: Stone, at para. 195.
 "Disease of the mind" is also a legal term. It is not a medical term although it contains a substantial medical component as well as a legal or policy component: Stone, at para. 195; R. v. Parks,  2 S.C.R. 871, at pp. 898-899; and R. v. Rabey, (1977) 17 O.R. (2d) (C.A.), at pp. 12-13, affirmed,  2 S.C.R. 513.
 In R. v. Cooper,  1 S.C.R. 1149, Dickson J. (as he then was) summarized the meaning of the term "disease of the mind" at page 1159:
In summary, one might say that in a legal sense "disease of the mind" embraces any illness, disorder or abnormal condition which impairs the human mind and its functioning, excluding however, self-induced states caused by alcohol or drugs, as well as transitory mental states such as hysteria or concussion. In order to support a defence of insanity the disease must, of course, be of such intensity as to render the accused incapable of appreciating the nature and quality of the violent act or of knowing that it is wrong.
 The term "disease of the mind" comprehends not only diseases that are physical in origin, but also purely functional disorders that have no physical cause: Rabey (Ont. C.A.), at pp. 14-16; Cooper, at p. 1159; R. v. Kemp,  1 Q.B. 399, at p. 406; R. v. Hartridge,  1 C.C.C. 346 (Sask. CA), at p. 366; and R. v. O'Brien,  3 C.C.C. 288 (N.B.S.C., A.D.), at pp. 305-306. What is critical is not so much the medical characterization of the condition or its origin in medical terms, but rather its effect on the capacity of the accused.
 Expert medical evidence about the cause, nature and symptoms of the abnormal condition from which an accused suffered and how that condition is viewed and characterized from a medical perspective is relevant to and admissible for a judge's determination of whether the condition constitutes a disease of the mind, and thus a mental disorder. Medical opinions are not dispositive of and sometimes of limited value in the ultimate decision of whether, in law, a condition amounts to a mental disorder: Rabey (Ont. C.A.), at p. 13;Stone, at para. 199; and Luedecke, at para. 103.
 To determine whether a condition amounts to a disease of the mind, a trial judge is to take a holistic approach informed by the internal cause factor, the continuing danger factor and other policy considerations: Stone, at para. 203. The internal cause factor refers to a malfunctioning of the mind that arises from a source in the accused's psychological or emotional make-up, as opposed to being produced by a specific external factor, such as a concussion: Rabey (Ont. C.A.), at para. 59. Especially relevant to the continuing danger factor are the psychiatric history of the accused and the likelihood that the trigger alleged to have caused the automatistic episode will recur: Stone, at para. 214.