1. Essentially, Euthanasia is a tool for minimizing unwanted or unnecessary suffering. It literally means the provision of "good death". There is active and passive, direct and indirect.
Suicide could be considered, and I have seen it as such, as self-euthanasia. When a doctor or individual helps another person engage commit suicide by giving him the means, he's engaging in facilitated indirect euthanasia facilitated self-euthanasia.
2. I am not against Euthanasia in principle. I think people should have the option of eliminating their suffering if they are terminally ill, can't be helped. If they are capable of reasoning, they should be able to choose in those situations. This includes by both psychological and physical suffering when it cannot be helped and life is not worth living due.
I am wary of allowing suicide in some instances because people don't live in bubbles. They might have strong ethical duties toward others or obligations toward people that might outweigh their desire to die or at least mitigate their claim to the right to suicide, depending on the seriousness of their reasoning for wanting death. You need to factor in the impact of death on all parites affected, weighted for that seriousness, and give equal consideration for like interests.
For instance, one would have less justification for wanting to kill oneself if one's not in pain that's inescapable or in serious condition and is simply bored, but at the same time, has many dependents who will suffer economically, emotionally if he dies. Being bored doesn't absolve someone of duties to family, friends, creditors, etc.
I am not sure about a duty to die, though. I have thought about it, and I can see that, in some instances at leasts, people in some situations may have a lesser claim to continued life depending on the consequences to others should they continue to live. The duty to die becomes stronger if you have already lived a long, fulfilling life and your continuation will have significant life impacts on others for relatively little gain to yourself. For example, if you are a vegetative state, very old, and terminal. One of my old ethics texts had cases wherein people have spent their live savings keeping a vegetative family member alive, only for that terminal unaware person never to experience life again. The lives of the family was ruined keep that person alive. The family suffered and the recipient gained little or nothing from it.
In other cases, I am not sure how much someone should need to sacrifice for another. It becomes ambiguous how much of a burden is too much.
One article you might want to read, I found it interesting, was "A Duty to Die."
A Duty to Die
A citation:
One part of the recent SUPPORT study documented the financial aspects of caring for a dying member of a family. Only those who had illnesses severe enough to give them less than a 50% chance to live six more months were included in this study. When these patients survived their initial hospitalization and were discharged, about 1/3 required considerable caregiving from their families, in 20% of cases a family member had to quit work or make some other major lifestyle change, almost 1/3 of these families lost all of their savings, and just under 30% lost a major source of income.[5]
Personally, I wouldn't want to destroy my family's savings, life, or seriously burden them so I could have a small chance of living a few extra months. I would rather die at that stage.