So to you is the suicide in heaven or hell? The suicide who has placed their faith in Jesus but for some reason can't overcome.
Heaven, otherwise Christ failed in His mission to save His people from their sins. If a believer goes to Hell for a sin, then what penalty did Christ pay? None, they are paying it themselves. So, if a genuine true believer is struggling in this life, is not in the right state of mind(this having no weight in God's judgement), and so on, commits suicide, how then can God deny His Son's sacrifice that paid all of sin, once and for all?
It doesn't make sense to say that Jesus paid the penalty of our sins, then state that a specific sin leads people to Hell. The only "sin" that leads people to Hell is the rejection of Jesus Christ as the Son of God who died on the cross for our sins and resurrected on the third day for our justification. To reject this is to remain in condemnation, for those without Christ are already condemned.