There are so many things that people are "taught" will send them directly to hell; suicide, homosexuality, murder, greed (and whatever else is listed in the 7 deadly sins). I don't believe there is any set action that will automatically curse your soul to burn forever, I think it is more to do with intent and the reasoning behind it. Whether you make one bad choice and truly regret it or whether you continually make the same bad choice over and over with malicious intent determines what happens to you in the end. I also don't believe that any sin can be forgiven (contradictory huh?). I have seen some of the horrible things that humans can do to each other but the one that is completely unfathomable to me is stealing the innocence of a child. Some of the things I have seen would make your blood curdle and the most ironic thing is that those guys are generally the most religious and the most polite to adults. My only thought is that if people like that are going to be in heaven, then I don't want to go.
Anyway, sorry, I'm rambling LOL. I can't understand the reasoning behind suicide because I have never been in that situation, but I really don't believe that a loving God would punish someone for acting in the only way they felt they were able when they were pushed past their limits.