Islam and Suicide
Suicide is condemned in Islam. The person who commits suicide is guilty of committing one of the most major of sins, since it indicates that the person is not satisfied with what God decrees and ordains. For this reason, a person will be punished in Hell for the killing him/her self.
The Prophet Muhammad, may God bless and grant him peace, said,
“Whoever kills his self with a sharp pointed object, his sharp pointed object will be in his hand while he stabs himself in the belly with it in the fire of Hell forever and ever eternally. Whoever drinks poison and kills himself, he will sip from it in the fire of Hell forever and ever eternally. And whoever jumps off a mountain and kills himself, he will jump in the fire of Hell forever and ever eternally.”
Sahih Muslim: Kitab al-Iman, Bab: 47
According to mainstream Sunni belief, this statement applies to the person who intentionally kills him/her self out of grief while believing that suicide is permitted. Such a person will spend eternity in Hell. But, if a person kills himself for similar reasons while knowing full well that it is impermissible to do so, he/she will eventually make it to Heaven if he/she is a Muslim.