Ironically, society's demonization of suicide and suicidal people has negative consequences even from the standpoint of preventing suicide itself, as Chris points out:

I passionately hate that all of the mental health people are obligated by law to commit me to an asylum if they think I’m about to kill myself. They can’t be objective. You know, if they could talk to me without such stupid constraints, they might have prevented this very suicide

Does it overall cause more suicides than it prevents? I don't know. However, speaking as someone who has a history of clinical depression, if I'm ever in circumstances where I am contemplating suicide, I want people to commit me. Because when I'm functional I'd consider suicide to be completely and utterly awful. So where is the line here? When do we decide that someone is rational enough to decide on their own to end their existence and when not? These are certainly difficult questions, but it does seem that the majority of people who attempt suicide and do not have terminal illnesses are being essentially irrational. On the other hand, preferences are hard to break down here, and if the technology doesn't exist to cure someone then should they have a right to end it now rather than waiting years? Another thing to consider is that from a utilitarian perspective, committing suicide generally makes everyone around you absolutely miserable, and will then always cause pain for them. In that regard, committing suicide is either misguided or selfish.