Preliminary information:
I have asked the question What age was the youngest person without any illness to die by euthanasia by own sane willingness? [closed] in the History Stack Exchange site and was told in a comment that it should perhaps be asked here because it is a political topic. As such I have adapted the question to try to make it suitable and edited as requested in comments below.
I understand the nature of euthanasia being controversial/debatable as it is quite a complex subject. There are different types. Voluntary, non-voluntary and involuntary, each with the variants of passice and active, and assisted suicide being similar but different as it is done by the person themselves.
Few places have it legalized. And while there are cases of it being practiced, my question is specific.
Actual question:
Is there any place in the world where someone who does not suffer from any physical nor psychiatric problem can actually decide to painlessly end their life through a legal process where they aren't the ones doing it but someone else administerating it to them (for example, first being put into an unconscious state and then having their life taken), from their own proven sane choice regardless if they have a socially highly accepted moral reason such as friends/family dying, having a lonely life, etc?
Have there ever been any cases like that which I have described?
Further details:
As the process of it being accepted legally is quite extensive and requires valid reasons to be considered, my question focus on what other reasons have ever been accepted or if they're actually considered at all. Without exhausting it nor going too in depth into long detailing, some examples of reasons that I can think of are the person:
having some sort of religious belief that conducted them to make such decision.
desiring to not go through a painful death whenever it does happen and so wishing to make it as painlessly as possible while they can decide beforehand.
having thoroughly decided rationally that life is not worth enduring even after considering all aspects (that they know of) of the spectrum of the positive and negative sides of existence.
I believe I should stress the fact that I'm asking about it specifically in a legal way (permitted by law), active (death administered by someone other than the one dying) and intentional (the person dying having requested it by their own sane wishes without having being forced by anyone nor being drunk or drugged).
I have attempted to close as many loopholes as I could but any request for clarification, suggestions, improvements, doubt of meaning and others things about the question are appreciated in the comments bellow.
Caveat notice:
This is not a question that should be treated as any sort of suicide attention seeking. It is merely a question out of curiosity, knowledge and philosophical interest (though the question itself in this form not being suitable for Philosophy Stack Exchange) which I can not find information about, and don't know where else or how else to search/ask about (specially without worrying anyone). If still in doubt please explain how else I could learn about it.