Stephen J. Hucker, MB, BS, FRCP(C), FRCPsych
  Consultant Psychiatrist,
  Professor, Division of Forensic Psychiatry, University of Toronto

       Forensic Psychiatry. ca

Criminal Responsibility

The notion that an individual who suffers from mental disorder may not bear the full weight of responsibility for their actions dates back to ancient times. Although various approaches to a legal test for criminal responsibility date back centuries in the Anglo-American tradition, some major historical trials during the 19th century in Britain culminated in the enunciation of the so-called McNaughten Rules (1843) in which the Law Lords of Great Britain indicated that for an individual to be found Not Responsible for their act or omission, their mental disorder must render them unable to know the nature and quality of the act or that it was wrong.

In the years following, courts on both sides of the Atlantic struggled with the meaning of the individual words of this rule. At the present time in Canada the Criminal Code dictates a test, derived from McNaughten, stating that for an individual to found “Not Criminally Responsible”, they must have been unable, by virtue of mental disorder, to appreciate the nature and quality of the act or know that it is wrong. Within Canadian jurisprudence, these individual words have been subject to judicial interpretation.

Historical Landmarks in Criminal Responsibility Cases

Ancient times

Hebrews, Aristotle

13th Century


17th Century
  • Coke’s Institutes of the Laws of England
  • Four classes of non compos mentis
1724 – Trial of Edward Arnold ("Crazy Ned")

"Wild beast" test : "totally deprived of his understanding and memory, and does not know what he is doing, no more than an infant, than a brute, or a wild beast, such a one is never the object of punishment"

1800 – Trial of James Hadfield
  • Thomas Erskine argued "delusion … is the true character of insanity"
  • Lord Kenyon : "The prisoner, for his own sake, and for the sake of society at large, must not be discharged; for this is a case which concerns every man of every station, "from the king upon the throne to the beggar at the gate; people of both sexes and at all ages may, in an unfortunate frantic hour, fall victim to this man, who is not under the guidance of sound reason; and therefore it is absolutely necessary for the safety of society that he should be properly disposed of, all mercy and humanity being shown to this unfortunate creature."
No medical evidence in trials until after the Hadfield case
Dr. Johnstone's Medical Jurisprudence on Madness (1800)
1840 – Edward Oxford attempts to assassinate Queen Victoria

Lord Den man: "if some controlling disease was, in truth, the acting power within him which he could not resist, then he will not be responsible. It is not more important but difficult to lay down the rule by which you are to be governed.

The question is whether the prisoner was labouring under that species of insanity which satisfies you that he was quite unaware of the nature, character and consequences of the act that he was committing."

1843 – Daniel McNaughton shoots and kills secretary to Prime Minister Robert Peel
  • unanimous medical evidence of McNaughton’s insanity
  • acquittal causes a public outcry
  • House of Lords calls upon the fifteen judges of the Queen’s Bench to clarify the law on insanity
  • "M’Naghten Rule"
  • "It must be clearly proved that, at the time of committing the act, the part accused was labouring under such a defect of reason, from disease of the mind, as not to know the nature and quality of the act he was doing; or if he did know it, that he did not know that was he was doing was wrong."
  • Concern over the meaning of "know" and "wrong" 
1869 – State v. Pike

Chief Justice Perley : if the killing was "the offspring of insanity, the defendant must be found not guilty" (New Hampshire doctrine)

1954 – Bazelon
  • DC Court of Appeals: "an accused is not criminally responsible if his unlawful act was the product of mental disease or defect" (Durham Rule)
  • Bazelon himself later expresses disappointment that psychiatrists failed to adequately present the courts with their expertise

2000 – Criminal Code of Canada

  • Section 16
  • (1) Defence of Mental Disorder – No person is criminally responsible for an act committed or an omission made while suffering from a mental disorder that rendered a person incapable of appreciating the nature and quality of the act or omission or of knowing that it was wrong.
  • (2) Presumption – Every person is presumed not to suffer from a mental disorder so as to be exempt from criminal responsibility by virtue of subsection (1), until the contrary is proved on the balance of probabilities
  • (3) Burden of Proof – The burden of proof that an accused was suffering from a mental disorder so as to be exempt from responsibility is on the party that raises the issue.

Definition of Terms: Legal Criteria Under Criminal Code of Canada for a Defense of “Not Criminally Responsible"

“Mental disorder”

  • defined in the Criminal Code of Canada as a “disease of the mind”
  • can include any mental abnormality which causes impairment with the exception of voluntary intoxication or transient mental states such as hysteria or concussion
  • consequently, personality disorders are eligible for this defence. At the present time this is uncommon, largely because appellate court decisions have rendered it unlikely that an individual with a personality disorder would be unable to appreciate the nature and quality of the act in the manner that the courts have ruled.


  • implies an ability to foresee and measure consequences and not simply “to know” in the cognitive sense.

"Nature and quality”

- refers to the physical consequences of an act.

“Knowing that the act or omission was wrong"

  • implies knowledge of both legal and moral wrongfulness. "Moral" means according to societal rather than individual moral code of the accused. It is insufficient that the individual simply chooses to follow their own moral dictates when they have the capacity to understand that it is wrong in the eyes of the law and wrong according to society’s usual standards.
  • the accused must have the ability to apply that knowledge rationally

What Does A Psychiatrist Need To Assess "Not Criminally Responsible" Issue:

  1. Crown’s file including police reports, witness and victim statements
  2. Previous psychiatric records
  3. Autopsy report
  4. Clinical interview with accused
  5. Mental status examination of accused
  6. Direct questioning of accused regarding knowledge of wrongfulness
  7. Detailed account from accused about circumstances of offense
  8. Possible psychological testing
  9. Possible neurological examination(s)

Patterns of Criminality and Mental Disorder

  1. Crime was a response to psychotic symptoms, such as delusions and hallucinations – many will be NCR
  2. Crime motivated by compulsive urges, such as paraphilias or disorders of impulse control – most not NCR
  3. Crime the result of a personality disorder
  4. Coincidental mental disorder not related to crime
  5. Mental disorder results from the crime – dissociation, depression
  6. Malingered mental disorder to avoid responsibility

Factors To Be Considered In Assessing Criminal Responsibility

  1. Evidence of mental disorder currently, in the past and at time of offense
    presence of delusions, mood disorder
  2. Motive for offense
    - if no apparent motive other than psychotic, suggests valid mental disorder
    - if rational motive also present, such as profit, suspect malingering or coincidental mental disorder
  3. Consider planning and preparation for crime
  4. Evidence of impaired functioning within a few days of the crime
  5. Detailed understanding of accused’s thinking and behaviour before, during and after crime
    - evidence of bizarre behaviour
    - attempt to escape or avoid detection
  6. Consider criminal record and personality disorder
  7. Consider previous psychiatric history
  8. Do previous hospital records describe delusions or hallucinations that relate to current offense
  9. If accused did not know the act was wrong, was this due to mental disorder?

Evidence of Knowledge of Wrongfulness

  1. Efforts to avoid detection
    - wearing gloves during crime
    - waiting until dark
    - taking victim to an isolated place
    - wearing mask or disguise
    - concealment of a weapon on way to crime
    - falsifying documents (passport, firearm permit)
    - giving a false name
    - threatening to kill witnesses if they report to police
    - giving a false alibi
  2. Disposing of evidence
    - wiping off fingerprints
    - washing off blood
    - discarding of murder weapon
    - burying a murder victim secretly
    - destroying incriminating documents
  3. Efforts to avoid detection
    - fleeing from the crime scene
    - fleeing from the police
    - lying to the police
  4. Statement by the defendant that he or she knew the act was wrong at the time of the offense
  5. Notifying the police that a crime was committed
  6. Expression of remorse or guilt after the crime committed
  7. Absence of hallucinations or delusions suggesting that the offense was justified

What Mental Disorders Qualify for an NCR Defence?

Psychiatric Symptoms and the NCR Defense

Command Hallucinations

Paranoid Delusions

Tactical Issues That May Be Used in Cross-Examining Experts

  1. Understanding of the legal test
  2. studies revealing poor knowledge of experts on the prevailing standard (eg. approximately 40% understand current meaning of “appreciate”)
  3. Demonstration of bias
  4. Focus on possible malingering
  5. Emphasize non-psychotic motives

Automatism refers to activity performed without conscious awareness and usually followed by complete amnesia. Since R. v. Kemp (1956) an artificial distinction has been made between insane and non-insane automatisms based on whether or not the condition arose from intrinsic factors. This special category of defence to a criminal charge, is defined in a leading Canadian case as:

  • “unconscious, involuntary behaviour, the state of 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.” (R v. Rabey, 1981)

Current law requires a two-step approach (R.v. Stone, (1999) 2 S.C.R. 290):

  • Defense must provide evidence to enable the trial judge to instruct a jury that, on the balance of probabilities, the accused acted involuntarily. Psychiatric evidence is required as well as consideration of such factors as: severity of the triggering stimulus, evidence of bystanders, history of automatistic-like dissociative states, evidence of motive, and whether the alleged trigger of the automatism was also the victim.
  • Judge must determine whether it is a mental disorder or non-mental disorder automatism
  • The first consideration is whether or not there is a mental disorder. There are two approaches to this that should be considered holistically rather than alternatively:
    1. How a normal person would react in the same circumstances – an extremely shocking trigger would be required in a normal person;
    2. Any condition likely to present a recurring danger to the public should be treated as a disease of the mind. Absence of continuing danger however does not preclude a finding of disease of the mind. Psychiatric evidence is relevant.

Mental Disorder Automatism

The determination of this is left to the fact finder (judge or jury). Cases proceed like any other Section 16 case.

Certain clinical conditions may produce "mental disorder automatisms":

  • Catatonic schizophrenia
  • Cerebral tumour
  • Cerebral vascular disease
  • Epilepsy - especially the type known as temporal lobe epilepsy (TLE) or complex partial seizures

    Several criteria have been proposed though cases have been reliably reported in which many were not present:
    •   Unequivocal evidence of epilepsy (though not necessarily of automatisms)
    •   Crime was sudden and with no obvious motive – no planning or premeditation
    •   Crime appears senseless and there was typically no attempt at concealment   or escape
    •   Abnormal behaviour was of brief duration (minutes rather than hours) and   never entirely appropriate to the circumstances
    •   Witnesses may have noticed impairment of awareness (e.g. inappropriate   actions or gestures, stereotypic movements, unresponsiveness, irrelevant   replies to questions, aimless wandering, dazed, vacant expression)
    •   Amnesia the rule but no continuing anterograde amnesia for events following   resumption of conscious awareness

  • Dissociative States:
    • Conditions in which there is loss of the usual integration of personal identity and memories, sensory and motor functions
    • There is a splitting off of specific mental activities from the rest of conscious awareness (eg. A commonplace example would be driving to work while focusing on the day in court and arriving with no memory of the actual drive)
    • Dissociative Disorders are severe, result in diverse and significant impairment of functioning fairly common
    • Are often associated with childhood physical or sexual abuse
    • Dissociative symptoms may occur in a number of other psychiatric disorders (e.g. conversion disorder, acute and chronic post traumatic stress disorder, borderline personality disorder, major depression, acute schizophrenia, etc.)
    • Several major subtypes exist:
      - dissociative amnesia
      - dissociative fugue – state of wandering often with confusion about one’s    personal identity or even adoption of a new identity
      - Dissociative Identity Disorder (“Multiple Personality Disorder”)
      - Depersonalization Disorder
      - Dissociative Disorder, not otherwise specified

Non-mental Disorder Automatism
These can be determined by the trial judge alone and results in a complete acquittal.

Certain clinical conditions may cause Non-Mental Disorder Automatism:

  • Cerebral concussion
  • Hypoglycemia (low blood sugar)
  • Drugs (medically administered)
  • Alcohol – idiosyncratic or pathological intoxication
  • Dissociative state – see above
  • Sleepwalking – Parks case
  • Parasomnias – behavioural phenomena inappropriate to the sleeping state
  • Commoner in childhood but can occur for the first time in adults
  • Violence can occur in various sleep disorders:
    • associated with sudden wakening
      – sleep drunkenness
      – confusion, disorientation, misinterpretation of reality on sudden arousal from deep (stage 3 or 4) sleep
      – may act as if defending against imagined attack
      – no subsequent recall
    • associated with sleepwalking
      – complex coordinated actions
      – includes destruction of surrounding objects, self injury or injury to others
      – victim usually a spouse
      – repeat actions actually common and repeated
      – genetic predisposition
      – may be precipitated by external factors
    • night terrors
      – probably commonest parasomnia
      – may have some recall of a frightening dream
      – behaviour suggestive of night terror witnessed by others
      - REM sleep behaviour disorder
      – mainly elderly men
      – 50% neurological disorder – none with psychiatric abnormality
      – dream enactment during REM

References & Further Reading:
Supreme Court Cases:
Rv Oomen, (1994) SCC (CB 671)
R.v. Cooper (1980) 1 S.C.R. 1149
R.v Simpson (1977), 35 CCC (2d) 337
R.v Barnier (1980), 51 CCC (2d) 193, 109 DLR (3d) 257
R.v Abbey, (1982) 68 CCC (2d) 394 (SCC)
R. v. Chaulk, (1990) 3 S.C.R. 1303
R.v. Stone, (1999) 2 S.C.R. 290
Rabey v. The Queen, [1980] 2 S.C.R. 513, aff'g (1977), 17 O.R. (2d) 1

Further Reading:
MacDonald, N., Hucker, S.J., Hébert, P.C. (2010) “The crime of mental illness.” Editorial, Canadian Medical Association Journal,182(13):1399.

Desmarais, S.L., Hucker, S.J., Brink, J., and DeFreitas, K. (2008) “A Canadian Example of Insanity Defence Reform: Accused Found Not Criminally Responsible Before and After the Winko Decision.” International Journal of Forensic Mental Health, 7 (1), 1-14 .

Desmarais, S.L. & Hucker, S.J. Multi-site Follow-up Study of Mentally Disordered Accused: An Examination of Individuals Found Not Criminally Responsible & Unfit To Stand Trial. Research & Statistics Division, Department of Justice, Canada. June 2005.

Hucker, S.J . & DeFreitas, K. (2005) “Criminal responsibility”. In Encyclopedia of Forensic & Legal Medicine.Payne-Jones, J., Byard, R., Cory, T. & Henderson, C. (eds). Elsevier: Oxford.

Livingston, James, D., Wilson, Derek, Tien George, Bond, Lynda. (2003). "A Follow-Up Study of Persons Found Not Criminally Responsible on Account of Mental Disorder in British Columbia". Canadian Journal of Psychiatry. July.

Bloom, H. "Psychiatric Issues in the Criminal Process". in A Practical Guide to Mental Health Law, Capacity and Consent Law of Ontario. Hy Bloom and Michael Bay (eds). Carswell. 1996. pp 255-292.

Hucker, S. J. , Webster, C. D., & Ben-Aron, M. H. (Eds.). (1981). Mental Disorder and Criminal Responsibility. Toronto: Butterworths.

© Stephen Hucker, MB,BS, FRCP(C), FRCPsych 2003 - 2011
This material is provided for personal use only. Any other use is strictly forbidden without the express written permission of the author.
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