Is it permissible to request euthanasia for someone who has been suffering from severe depression for many years and has not found any benefit in psychological or spiritual treatment?

It is impermissible for a Muslim to commit suicide for any reason, due to the Almighty's saying: "And do not kill yourselves. Indeed, Allah is to you ever Merciful," and due to the Prophet's (peace be upon him) saying: "Whoever kills himself with a piece of iron, that iron will remain in his hand, and he will keep thrusting it into his belly in the Fire of Hell, abiding eternally therein forever. And whoever drinks poison and kills himself, he will keep sipping it in the Fire of Hell, abiding eternally therein forever. And whoever throws himself from a mountain and kills himself, he will keep throwing himself down in the Fire of Hell, abiding eternally therein forever." Contemporary jurists have unanimously affirmed its prohibition. Thus, it is not permissible to kill a patient out of despair of their recovery.