Thanks for the responses, good food for thought here. I agree strongly with Elysium's point on "quantity of life over quality", in my experience (I know I know anecdotal) the mental health care process for some illnesses seems to be very much "treat the symptoms" so that the patient is well enough to survive. The quality of life does not seem to be considered.

On the flipside, I can also clearly envision the protracted proceedings and possibility that we should be focusing on better palliative care and not on terminating the patient. Clearly it is not a simple issue, it is one that would need to be carefully evaluated on a case by case basis. I do however believe that there are rational humans (I am going to be egotistic and suggest that I am at least partly rational) that would like to have the choice to end their lives in a safe and comfortable fashion when they choose to die. Nature has no regard for comfort, so in my mind it is up to humanity to provide this comfort.

The alternative is forcing a person into a position where they need to end their own life if they wish to do so (after all treatment avenues have been exhausted), which could have terrible results for the individual choosing to end their life and for their family (since they cannot really speak of such things at the moment without the threat of incarceration). It seems to me that an open dialog on the matter with the possibility that the person can visit a hospital and with the consent of their immediate family go to sleep is far better than the alternative.