Reasons for judgement were released this week by the BC Court of Appeal confirming that judges must award damages when pre-existing conditions are aggravated in part due to a tortious cause.
In this week’s case (Sangha v. Chen) the Plaintiff was involved in a 2005 intersection crash. Both the Plaintiff and Defendant were at fault for the incident. The trial judge assessed damages on the basis that the Plaintiff sustained a two year soft tissue injury. At the time of trial the Plaintiff had on-going chronic pain which was rooted in chronic depression which pre-dated the accident. However, the Court found that the collision physical injuries “aggravated his previous depressed state” but did not assess damages for the on-going worsened depression finding that the Plaintiff “would have suffered his current symptoms in any event“.
In finding that this was in error and that damages needed to be assessed to reflect the collision caused aggravation of pre-existing depression the BC Court of Appeal provided the following reasons:
 With respect, it does not appear to me to have been open to the judge to find, as she did in para. 110 that Mr. Sangha “would have suffered his current symptoms, in any event”, having found earlier in that same paragraph that “his physical injuries aggravated his previous depressed state”. Further, her conclusion that Mr. Sangha would have suffered his current symptoms appears to be inconsistent with her view expressed in para. 111 that “at most the injuries suffered in the accident aggravated the plaintiff’s mood symptoms”. Given that the “mood symptoms” are exactly those symptoms encompassed within the pre-existing condition of depressive illness, para. 111 appears to allow for attribution of at least a portion of Mr. Sangha’s current symptoms to the physical injuries sustained in the accident.
 I recognize that one must not parse a trial judge’s reasons for judgment with too much exactitude, and so I have turned to the evidence relied upon by the trial judge, the medical report of Dr. Riar, in her determination that all of Mr. Sangha’s current malady derives from his pre-existing condition. Nowhere in that report does Dr. Riar entirely dissociate the current condition of Mr. Sangha from the accident, so as to support the judge’s conclusion that Mr. Sangha would have suffered his current symptoms, in any event. While Dr. Riar clearly considered that the preponderance of Mr. Sangha’s current symptoms derive from the pre-existing mental illness, Dr. Riar also said “I feel that the accident in question aggravated his mood symptoms, which in turn fed into his pains, and they have continued like that all along” and “The only thing the accident did was complicate his situation somewhat more”. Questioned about this, Dr. Riar affirmed this view of the reflection to at least a small degree, of the physical injuries in Mr. Sangha’s current malady:…
 The correct approach to pre-existing conditions is discussed in Athey v. Leonati,  3 S.C.R. 458, under the rubric of “crumbling skull:
The so-called “crumbling skull” rule simply recognizes that the pre-existing condition was inherent in the plaintiff’s “original position”. The defendant need not put the plaintiff in a position better than his or her original position. The defendant is liable for the injuries caused, even if they are extreme, but need not compensate the plaintiff for any debilitating effects of the pre-existing condition which the plaintiff would have experienced anyway. The defendant is liable for the additional damage but not the pre-existing damage: Cooper-Stephenson, supra, at pp. 779-780 and John Munkman, Damages for Personal Injuries and Death (9th ed. 1993), at pp. 39-40. Likewise, if there is a measurable risk that the pre-existing condition would have detrimentally affected the plaintiff in the future, regardless of the defendant’s negligence, then this can be taken into account in reducing the overall award: Graham v. Rourke, 74 D.L.R. (4th) 1; Malec v. J. C. Hutton Proprietary Ltd., 169 C.L.R. 638; Cooper-Stephenson, supra, at pp. 851-852. This is consistent with the general rule that the plaintiff must be returned to the position he would have been in, with all of its attendant risks and shortcomings, and not a better position.
 I also refer to Blackwater v. Plint, 2005 SCC 58,  3 S.C.R., 2005 SCC 58.:
 It is important to distinguish between causation as the source of the loss and the rules of damage assessment in tort. The rules of causation consider generally whether “but for” the defendant’s acts, the plaintiff’s damages would have been incurred on a balance of probabilities. Even though there may be several tortious and non-tortious causes of injury, so long as the defendant’s act is a cause of the plaintiff’s damage, the defendant is fully liable for that damage. The rules of damages then consider what the original position of the plaintiff would have been. The governing principle is that the defendant need not put the plaintiff in a better position than his original position and should not compensate the plaintiff for any damages he would have suffered anyway: Athey. …
 I respectfully conclude that the judge erred in failing to reflect, in her damages award, her conclusion of fact that “the physical injuries aggravated his previous depressed state” and “the accident did cause at least some of” the psychological symptoms. To what extent the damages should have been adjusted to account for these conclusions I cannot say. That question is one particularly within the purview of a trial judge. Accordingly, in my view, the award of damages must be set aside and the issue of quantum of damages must be remitted to the Supreme Court of British Columbia for fresh assessment.