The alleged "mental illness" or lack thereof should not even come up as relevant subject matter in a competency hearing. It has no bearing on the subject.
Danger to self or others, except insofar as it demonstratably stems from an inability of the person in question to plan, make observations, and comprehend likely outcomes, is also not relevant, even where it can be supported by explicit evidence of actual behavior rather than prediction. You have the right to make incredibly stupid decisions (and the obligation to be held responsible for having made them) as long as you are competent.
Hearings into competency should not be segregated in such a way that there would exist courts into which only the allegedly "mentally ill" are brought. They need to have their hearings in the same venue as any other competency hearing. The tendency I've observed is for the standard competency hearing to operate from an assumption of competency, which must be challenged by the parties alleging a lack thereof; whereas psychiatric commitment hearings tend to operate from an assumption that "you wouldn't be here if you didn't need it", leaving the burden of demonstrating otherwise to the person in question.
Original SDMB thread - Psychology, the law, and being committed
See my next post on this same thread
See my previous post on this same thread