Don't you think this could quickly devolve into legitimising suicide as something normal and valid, as opposed to something that should be avoided, through proper care, support and help?
If someone is sick, he will tend to get treatment for his sickness, be it mental or not. If someone refuses to treat himself (and this happens a lot for non-mental sickness), there is anyway little one can do.
Finally, I think looking at where the world is hurling toward and why, I feel it should be accepted by all that some individuals want to commit suicide as an altruistic gesture.