I'm not an official answerer for conversantlife, if official answerers exist, but I thought I would chime in nonetheless.

First, without having done an extensive search of the Bible, I cannot recall the Bible speaking to the issue of suicide directly and the consequences thereof. It would most likely fall under the category of murder, since one would be taking their own life, and in that sense it should be understood as sin.

On the issue of whether it is forgivable, we must answer "we don't know". It would be dangerous and irresponsible for us to go one way or the other precisely because the Bible does not speak directly to this issue. Since it is a sin, and one that the person who commits it wouldn't be able to ask forgiveness for, we cannot say that is positively forgivable. On the other hand, we know that God judges the heart which we cannot see or know - so we cannot say that it is positively unforgivable.

This may not be the answer you were looking for. Unfortunately, tough issues like this are not always easily answerable. But we should take hope in knowing that God is a good God, he is a just God, and he is a merciful God. Whatever the right decision is, God will make it.