Although the concept of intent plays a far more central role in criminal law than in personal injury lawsuits, the lack of ability to form intent can indeed take away culpability for otherwise seemingly negligent actions. Reasons for judgement were released today by the BC Supreme Court, Vancouver Registry discussing this.
In today’s case (SH v. AM) the Plaintiff was injured in a vehicle collision. The Defendant denied fault in part arguing that at the time of the collision he “was suffering a psychotic episode” and was not responsible.
The Plaintiff sought to have this defense struck on an application on a point of law arguing the defense could not succeed but the Court refused to strike it finding the evidence needed to be weighed at a full trial. In addressing the merits of such a potential defense in a BC personal injury lawsuit Madam Justice Burke provided the following reasons:
 The plaintiff relies in particular on Wenden v. Trikha, 1993 CarswellAlta 528 at para. 17 (C.A.), leave to appeal ref’d  S.C.C.A. No. 126, as follows:
 In order to succeed, the patient would have to prove a sudden reversal of facts. First, he would have to prove that when he was well enough mentally that he could be liable for negligence, he had no reason to foresee any danger from his possessing an automobile or car keys or not taking his medication. Then he would have to prove a sudden change in condition, his suddenly becoming too insane to be liable for negligence, and that that condition continued without let-up until the time of the collision. If he did not prove the first item, then he would be negligent in having let himself slip into Insanity while having access to an automobile (or vice versa). If he did not prove the second item, then the defence of insanity would simply be irrelevant. It does not seem to us that either was proved here. [Emphasis added.]
16] The parties also essentially agree the legal analysis for the determination of whether a person with a mental illness is liable for negligence includes whether the act was a conscious act of the defendant and whether the onset of the incapacity to control his or her actions was foreseeable and reasonable steps could have been taken to prevent it: Hagg; Fiala…
 A review of the judgment in Hagg is helpful in understanding what is needed to come to a conclusion in this matter. At 390-91 of that judgment, while not deciding the matter, the BC Court of Appeal states:
I find it unnecessary to consider whether, as seems to be indicated in Roach, J.A.’s judgment in Buckley & T.T.C. v. Smith Transport Ltd., a driver whose mind is so ravaged by disease that he does not understand the duty which rests upon him to take care, as distinct from one who is prevented from discharging that duty, cannot be held liable for his acts and omissions in the course of his driving. I reserve this for some future occasion. I am unable to find evidence establishing, directly or by reasonable inference, that the appellant in the case at bar did not understand the duty to take care which rested upon him. Likewise, I reserve until the occasion arises the question whether insanity which does not result in impairment of faculties and judgment to the full extent I have mentioned will provide a defence to an action for negligence.
 The question I am in essence being asked to decide is whether the defendant in this case had “a mind so ravaged by disease that he does not understand the duty which rests upon him to take care, as distinct from one who is prevented from discharging that duty.” In the former, the individual cannot be held liable for his acts and omissions in the course of driving.
 It is apparent to me that in order for a conclusion to be reached on this point, I must weigh the evidence. The plaintiff argues the onset of the psychiatric condition was foreseeable and reasonable steps could have been taken to prevent it. The plaintiff asks me to reach that conclusion after reviewing the discovery evidence and contrasting it with the psychiatric opinions. The plaintiff also points to what she maintains is inconsistencies, in particular in Dr. Cheng’s report, on the question of whether the defendant had periods of lucidity where he knew or should have known that he should have taken steps to ensure his psychotic state did not happen or that he should not get in the car, as per the situation in Wenden. He also contrasts portions of Dr. Levin’s report on the basis of his conclusion on this point and refers to a time subsequent to the accident.
 All of this makes clear I am being asked to weigh the evidence in order to come to a conclusion as to whether the defendant understood the duty that rested upon him to take care. In my view, that is not something that can be done under R. 9-4. This Rule is reserved for the determination of points of law without the need to weigh evidence.
 I note further the inconsistencies that are pointed to could well be explained by testimony of the experts. The discovery evidence in isolation is difficult to reconcile with the differences between the parties. It is very difficult in these circumstances to come to the conclusion on the evidence on this basis. In my view, this is more appropriately left to the trial judge to determine.
 As noted in Larsen, R. 9-4 can be used where the point of law arises on the pleadings and can be determined without hearing evidence. While the plaintiff says the facts in the pleadings are not in dispute, the reality is a conclusion on a crucial point in this litigation can only be reached by weighing the evidence provided in the affidavit material. This is not consistent with the comments in Larsenand Golden Gate Seafood.
 While I am sympathetic to the concern of costs of a 10-day trial raised by the parties, I also note this is an important issue with far-reaching consequences. Jurisprudence has been cited to me from Alberta and other jurisdictions. It has not, however, been definitively dealt with in the B.C. courts. I also note it may be that the parties are able to reach agreements on the evidence such that only the points of contention are proffered for testing in a trial setting.
 The application is therefore dismissed.