In light of Robin Williams‘ tragic death there are a lot of people saying a lot of different things about Christianity and suicide. I thought it would be useful to take a moment to consider the wisdom the Catechism has to offer.
“Grave psychological disturbances, anguish, or grave fear of hardship, suffering, or torture can diminish the responsibility of the one committing suicide. We should not despair of the eternal salvation of persons who have taken their own lives. By ways known to him alone, God can provide the opportunity for salutary repentance. The Church prays for persons who have taken their own lives.” - Catechism of the Catholic Church, Paragraph 2282-2283