To be absolutely blunt, suicide is murder of ones self. It also demonstrates that the committer of such an act has no faith, is unbeliving and is fearful.
The Bible is quite clear about the fate of those who have no faith in God and who do not REPENT, TURN AWAY FROM and CEASE from those sinful acts.....

But the fearful, and unbelieving, and the abominable, and murderers, and whoremongers, and sorcerers, and idolaters, and all liars, shall have their part in the lake which burneth with fire and brimstone: which is the second death. Rev 21:8