I think it's not clear from the reading. The language is not straightforward. The fact that a Criminal Code provision is vague and open to interpretation would suggest to me that someone who is suffering from purely a psychological condition might also qualify here. That being said I think that the psychological impairment that comes from intense or chronic pain automatically puts into question whether that individual is able to give informed consent and has the capacity to do so. Psychological impairment automatically lowers the ability of that patient to be able to give a clear consent that is not inhibited by psychological factors.
On May 3rd, 2016. See this statement in context.