I feel that everybody is pretty much alone with their problems, since nobody truly knows what someone has to deal with and thoughts/ worries going on in their head on a daily basis. Even if you had/have a great family or relationshp, or friend to talk to there are certain things unsaid or having to deal with yourself even in the best of them. Certain things can come up that you still have to deal with alone, and you may still don't know how to go about solving them on your own. They may be bad, or even really bad. This by no means makes anyone crazy IMO, but everyone has their limit, and everyone goes through a different path in life. Suicide is an escape it seems, and should be an individual's own decision. Right or wrong.
I do feel however if another life is involved with that person, as an infant (children) for example, that depend on that person for their well being, that the right choice would be to get through their depression no matter how rough it may be. For the children's children's sake. They depend on you. It is more serious now when you are the provider and care for others who cannot fend for themselves or are too young to. If you are married, and your spouse depends on you then that would apply as well....
As for family and friends, they are adults and have their own lives. The thoughts of suicide bieng a "selfish act" comming from that perspective (single) always seems like close-minded ignorant thinking to me. Family is great, but as we grow older everyone usally goes their seperate ways and in most cases with the exception of exceptional family relationships, can't or don't really want to hear about your problems too much as I am sure they are focused on thir own. Sucks,...but seems to be somewhat true as I see it most of the time.
Just my opinion on the subj.
BT