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R v Kirton and the Effects of Psychological Assessment on Sentencing - Nicholas Warsza


In 2020, the Manitoba Court of Appeal released a judgement on a dispute of the sentence of Jason Kirton. Mr. Kirton asserted the sentencing judge erred in his sentencing of Kirton, and the expert psychological evidence gained throughout the trial was invalid. This paper aims to explore the effect of physiological assessment on the sentencing of offenders. Jason Kirton’s appeal will first be summarized, then an analysis of the appeal with a study on psychological assessment being applied to the facts of the appeal. This paper will demonstrate that a psychological assessment has no significant impact on the length of the sentence.


Mr. Jason Kirton was convicted of six offences: breaking and entering into a dwelling-house and committing an indictable offence; aggravated assault; assault with a weapon; possession of a loaded restricted firearm; possession of a firearm contrary to a prohibition order (X2). As such, Kirton was deemed a dangerous offender and ‘sentenced to an indeterminate sentence in relation to counts 1, 2, and 3’ and was handed a five year sentence for count four ‘a one-year consecutive sentence for count 7 and a one-year concurrent sentence for count 8’. Kirton appealed his sentence and convictions. The conviction appeal was dismissed. The accused sought to appeal his sentence on the basis that: ‘the sentencing judge erred when he found the accused to be a dangerous offender and imposed an indeterminate sentence on the predicate offences (counts 1, 2 and 3); and the sentencing judge erred when he failed to credit the accused for pre-sentence custody at the rate of 1.5:1 in relation to counts 4, 7 and 8’. The Crown was in agreement that the custody served by the accused pre-sentencing was not accounted for by the sentencing judge, and did not oppose that the sentences for offence 4, 7, and 8 were adjusted.


The courts are left with the issue of whether the sentencing judge ruled appropriately by finding the accused ‘to be a dangerous offender and in deciding that an indeterminate sentence was appropriate’.


The courts dismissed the appellant’s appeal of the dangerous offender designation and the indeterminate sentence because he ‘failed to identify any error that would justify appellate intervention’.


The Department of Justice describes an indeterminate sentence as one declared against a ‘dangerous offender and sentenced to an indeterminate period of detention’—this sentence does not have a definite end date, and the Parole Board of Canada will review the case after seven years of detention. The appellate court judge considered the accused argument that the sentencing judge ‘placed too much weight on the evidence of the Crown’s expert,’ particularly because the Doctor had never taken a one-on-one treatment with a similar offender to the accused, and did not consider the appellant’s statements of his new behaviour and positive steps he was taking in life. The appellate justice analyzed the doctors investigation including 9.25 hours of interviewing the accused and ‘19 volumes of background materials detailing the accused’s personal, familial, education and employment history, previous offending, institutional programming and behaviour and supervision history’. The appellate judge also used comments from the Ontario Court of Appeal to show the process used by the sentencing judge was in line with other courts handling similar matters. It is important to note that in Canada, the courts have adopted quite a general definition of psychological impairment. Justice Dickson said in Cooper, that a psychological impairment ‘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 the Kirton case, along with a ‘severe and chronic’ substance use disorder, Dr. Woodside also found that the accused showed ‘significant psychopathic traits’ and met the criteria to be diagnosed with severe antisocial personality disorder. Antisocial Personality Disorder ‘is a potent predictor of future violent behaviour’. So, what happens when courts are presented with an offender like this, and what effect does it have on the sentence imposed on a guilty offender?

A team of researchers undertook to analyze just this situation. In 2004, researchers at the University of Zurich published an article in the International Journal of Law and Psychiatry called The Relationship Between Defendant’s Social Attributes, Psychiatric Assessment and Sentencing. While Kirton believes he received an unfair sentence due to his psychiatric assessment, what Ribeaud and Manzoni show is quite interesting. In analyzing psychiatric assessment and attribution of diminished responsibility, the researchers found that where psychiatric assessment of an accused took place, 67.6% were attributed to have diminished responsibility. Alternatively, of those who were not assessed only 11.1% were attributed to have diminished responsibility. Against the researchers original hypothesis, it was found that ‘diminished responsibility has a negative but nonsignificant effect on sentence length’ and suggest ‘that, on average, judges did not take into consideration attributions of diminished responsibility in their sentences’. Clearly, while judges do consider the responsibility level of those convicted after psychological assessment, they are also considering other factors. An attribution of psychological disorders were not found in their study to have a result of increased sentence length. If there are any questions even after the appeal as to whether the courts erred in their sentencing of Kirton, one need only to look at this study from Switzerland to see that this is not the case. While Kirton’s sentence has no end date, data suggests that the psychological assessment did not have an impact on this and the judge still may have found him to be a dangerous offender. Although the study took place in a different jurisdiction, it affirms that the practice of not reducing or extending sentences even for those under psychological assessment is international judicial practice.


One could certainly perform more research on this topic, and especially in the Canadian context (no relevant literature on the topic of mental health assessments and sentencing was found during research). With the case presented as well as the data and study reviewed from The University of Zurich, mental health assessments may add explanation to an offender’s actions and assist in justifying a sentence, but it certainly does not in any substantive way increase or decrease the sentence of a guilty offender.


1 R v Kirton, 2020 MBCA 113, at para 4, [Kirton].

2 Ibid, at para 2.

3 Kirton, supra at para 1.

4 Kirton, supra note 1 at para 2-3.

5 Kirton, supra note 1 at para 3.

6 Kirton, supra note 1 at para 4.

7 Kirton, supra note 1 at para 5.

8 Kirton, supra note 1 at para 6.

9 Kirton, supra note 1 at para 20.

10 ‘How Sentences are Imposed’ (last modified 13 September 2018), online: Department of Justice


11 Kirton, supra note 1 at para 8-9.

12 Kirton, supra note 1 at para 15.

13 Kirton, supra note 1 at para 18.

14 R v Cooper, [1980] 1 SCR 1149, at 1150.

15 Kirton, supra note 1 at para 12.

16 Kirton, supra note 1 at para 12

17 Denis Ribeaud & Patrik Manzoni, ‘The Relationship Between Defendant’s Social Attributes, Psychiatric Assessment and Sentencing—A Case Study in Switzerland’ (2004) 24 IJLP 375 at 382 (QL).

18 Ibid, at 382.

19 Ribeaud, supra note 15 at 383.


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