On another board, a sad discussion was the topic. Apparently someone who a poster knows quite well committed suicide.
That discussion caused quite a debate, as you can probably imagine. It was quite emotionally charged.
One particular poster said that if someone commits suicide, it proves that they were not a genuine Christian.
Can we know that for sure, based on Scripture?
We do not know what was going on in their minds at time of the suicide, and believe that the scriptures teach that a genuine christian can still sin at times and still be saved, so there sin of killing themselves would not negate the eternal life in Christ God gifted them with at salvation. They will appear before the Lord to gave a reasoning and accounting for this, but would be in Heaven.
The person who said that suicide proves the person was not a true Christian, believes 1Cor. 3:16-17, as well as the doctrine of the Perseverance of the Saints, proves this. He has a hard time believing that God would allow a true Christian to get into such a bad state that they would commit suicide.
Another Scripture he uses is Romans 8:28. Saying if God works all things out for good for those who love Him. How could it be that "suicide" is the "good" that the verse is talking about? Therefore the person says, suicide is an act done by a non-Christian.
Could the Lord be taking the person home, though, knowing that they will not be able to function in a right frame of mind and bring dishonor to name of Christ?
Despite the plans of the evil one, God still would use it for the good?
Certain conditions, if they remain persistent and intense enough, can cause changes in brain chemistry and such to the extent that insanity can drive one to self-destruction. I had a life-threatening bout with severe clinically measurable depression that grew darker and darker over a period of months until it was interrupted - medically - following a suicide threat.
This does not mean that I was lost during that time, nor more than the prophet Elijiah who also suffered from depression to the point of seeking death.
Think that only the Lord really knows at times what is going on in a person mentally/emotionally, as we can be so quick to judge another person who has taken this action, but prefer to allow the Lord to deal with the family...