Proving Mental Injury

In its recent decision of Saadati v. Moorhead, 2017 SCC 28, the Supreme Court of Canada held that courts may award damages for mental injury based on the testimony of lay witnesses and without expert evidence establishing an identifiable medical diagnosis or condition.

The plaintiff was injured when his tractor-truck was struck by a vehicle driven by the defendant. The plaintiff sued the defendant for negligence, claiming he had suffered mental injury from the accident.

At the trial level, the BC Supreme Court found the accident had indeed caused the plaintiff’s psychological injury, including a personality change and cognitive difficulties. This finding was not based on an identified medical cause or expert evidence, but rather on the testimony of the plaintiff’s friends and family. These lay witnesses testified that the plaintiff was a funny, energetic, and charming individual prior to the accident, but had become sullen and prone to mood swings. His close relationships with others had deteriorated. The BC Supreme Court awarded the plaintiff $100,000 in non-pecuniary damages.

On appeal, the BC Court of Appeal reversed the trial judge’s decision, finding that the plaintiff’s claim could not succeed, as he had not demonstrated with expert evidence a medically recognized psychiatric or psychological injury.

The Supreme Court of Canada (SCC) restored the trial judge’s decision on the basis that a finding of legally compensable mental injury need not rest, in whole or in part, on the claimant proving a recognized psychiatric injury through expert evidence.

The law of negligence accords identical treatment to mental and physical injury.   As with physical injury, a plaintiff alleging mental injury still needs satisfy the criteria applicable to any successful action in negligence – i.e. the existence of a duty of care owed by the defendant to the plaintiff, a breach of that duty, and resulting harm to the plaintiff causally connected to the breach. In the case of mental injuries specifically, the plaintiff must also demonstrate that the injury is serious, prolonged, and rises above the ordinary annoyances, anxieties, and fears that come with living in civil society.

In Saadati, the SCC emphasized that a court adjudicating a claim of mental injury should not be concerned with diagnosis, but rather symptoms and their effects. There is no necessary relationship between reasonably foreseeable mental injury and a diagnostic classification scheme; rather, the court’s inquiry should be directed to the level of harm that the claimant’s particular symptoms represent, not whether a label could be attached to them. While expert evidence can assist in determining whether or not a mental injury has been shown, such evidence is not necessary, and a court can find mental injury based on other evidence, including the testimony of family and friends.

It remains open to the defendant, in rebutting a claim, to call expert evidence establishing that the accident cannot have caused any mental injury, or at least any mental injury known to psychiatry.

Based on the foregoing principles, the SCC found no legal error in the trial judge’s treatment of the lay witness testimony concerning the plaintiff’s mental symptoms, even in the absence of expert testimony associating them with an identified condition. The SCC restored the trial judge’s award of $100,000.