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killed them in their sleep with a kitchen knife. His mother-in-law died, and his father-in-law was seriously injured. He did not remember any of the actions and there was no reasonable motive for the murder. Parks did not have any mental conditions, although several members of his family had sleep problems. Parks had been working long hours at work and had recently been charged with a theft from his employer. He was acquitted both at trial and at the Court of Appeal.


  1. Does sleepwalking constitute non-insane automatism or is it a "disease of the mind" under s.16 of the Criminal Code?


Appeal dismissed.


Lamer held that the expert evidence showed that Parks was indeed sleepwalking at the time of the attack, that sleepwalking is not a neurological disorder, and that there is no medical treatment for sleepwalking aside from good health.

La Forest went into detail analyzing automatism. In determining whether or not automatism springs from a disease of the mind one should look to determine if it is caused by internal (in the mind) or external factors. One should also consider whether the condition is continuing. Although these are not determinative, a finding that automatism is internal and continuing suggests a disease of the mind. In this case there was no evidence of a recurrence of sleepwalking causing a similar outcome. Again La Forest states that whether or not something is a disease of the mind is a legal question – although expert evidence helps, it is not determinative.

There is also non-insane automatism, which is where the automatism is caused by external factors, it is not continual, and is not linked to any disease of the mind. This applies as a complete defence resulting in the disposition of an acquittal. Although some critics are against applying this defence to sleepwalking, La Forest states that it cannot lead to an opening of the floodgates because it is so rare, and that it must be done to uphold the principles of voluntariness required for a conviction.

Once the defendant raises automatism as a defence the burden is on the Crown to show that the acts were voluntary. They can also prove that the actions were the result of "insane" automatism.


  • Automatism works as a defence and results in an absolute acquittal.
  • Once the defendant raises automatism as a defence the burden is on the Crown to prove voluntariness, or alternatively to prove "insane" automatism which results in a non-criminal responsibility verdict but may result in an alternative disposition under s.672.54.