Capacity. B.L. v. Pytyck
In B.L. v. Pytyck (Ont CA, 2021) the Court of Appeal considered legal mental capacity in the context of deciding whether a party could consent or refuse to consent to treatment:
 I see no such error by the Board. With respect, B.L.’s submissions overlook an important element of the legal test as articulated by the Supreme Court in Starson. As the Board pointed out in its reasons, at p. 13, in Starson the Supreme Court stated, at para. 79:
While a patient need not agree with a particular diagnosis, if it is demonstrated that he has a mental “condition”, the patient must be able to recognize the possibility that he is affected by that condition. Professor Weisstub comments on this requirement as follows…: Accordingly, the Starson test for capacity in respect of the ability to appreciate the reasonably foreseeable consequences of a decision or lack of decision includes a requirement to consider whether a person’s condition results in an inability to recognize that he or she is affected by its manifestations, thereby rendering the person unable to apply the relevant information and appreciate the consequences of his or her decision. This aspect of the legal test has been repeated and applied by this court in several cases: Giecewicz v. Hastings, 2007 ONCA 890, 288 D.L.R. (4th) 587, at paras. 18-21, leave to appeal refused,  S.C.C.A. No. 97; D’Almeida v. Barron, 2010 ONCA 564, 103 O.R. (3d) 250, at paras. 24-26, leave to appeal to S.C.C. refused, (2011) 284 O.A.C. 400; Gajewski, at paras. 47-53; and Murray v. Alatishe, 2019 ONCA 596, at para. 20.
Condition refers to the broader manifestations of the illness rather than the existence of a discrete diagnosable pathology. The word condition allows the requirement for understanding to focus on the objectively discernible manifestations of the illness rather than the interpretation that is made of these manifestations.As a result, a patient is not required to describe his mental condition as an “illness”, or to otherwise characterize the condition in negative terms. Nor is a patient required to agree with the attending physician’s opinion regarding the cause of that condition. Nonetheless, if the patient’s condition results in him being unable to recognize that he is affected by its manifestations, he will be unable to apply the relevant information to his circumstances, and unable to appreciate the consequences of his decision. [Emphasis added.]