I may be able to add just a few more references to certain aspects of the Supreme Court's ruling that you might find interesting on this point.
The only place in the Supreme Court's judgment where it talks about mental illness is in paragraph 111, where it says:
Professor Montero’s affidavit reviews a number of recent, controversial, and high-profile cases of assistance in dying in Belgium which would not fall within the parameters suggested in these reasons, such as euthanasia for minors or persons with psychiatric disorders or minor medical conditions.
That's really the only place where it talks about it.
There are two other aspects of the court's ruling that I would bring to your attention, as you may find them relevant on this point. One is that there is a variety of places, mostly in the first half of the judgment, where it talks about Ms. Taylor and people like her and the kinds of conditions it had in mind. It mentions things like individuals with Huntington's disease or ALS, and individuals with terminal cancer. These are the kinds of medical conditions it actually talks about.
The final point that I would make that may be relevant is that a large part of the basis for the court's ruling that the absolute prohibition was unconstitutional was that it found that competence and vulnerability can be assessed on an individual basis. It said doctors already, when they're treating patients, individually assess that patient's mental competence, whether they're being coerced or making decisions that somebody else is pressuring them to make, whether they're thinking clearly. It was because the court had expressed confidence that Canadian physicians can assess both mental competence and the vulnerability of a person at the individual level that it felt the absolute prohibition was unconstitutional and you could provide physician-assisted dying to those who wanted it while protecting the vulnerable.