I do not believe that suicide is a one way ticket to eternal damnation as the Catholic Church for example knows. I do though believe that a suicide can go to hell based on their works on Earth. For example, Hitler undoubtedly is frying.
The Catholic Church does not hold the view that suicide is a one way ticket to eternal damnation.
I am a Catholic who has lost a close family member to suicide. The Church's view is that suicide is a grave sin which, if done with full knowledge of the gravity of the sin and with full consent and not repented of, merits Hell as all unrepentant mortal sins do.
My view is that it's a very open question whether people who commit suicide possess the ability to fully consent to their actions, and another open question as to whether someone who commits an act which leads to their death has time and ability to repent before death. Only God knows of these things in any individual's case. As such, we should operate under the assumption that a person who committed suicide is in (a very long stint in) purgatory, and pray for their soul as much as possible. If they aren't in purgatory, there's no harm in praying for them anyway, and we can't possibly know either way in this life.
For what is worth I remember something about suicide survivors that claimed that in most cases they tend to regret it after commiting suicide; in particular for those who opt for suicide by throwing themselves off a cliff, building or some other high place. Though I can't remember if this was just anecdotal evidence or if it was a genuine study.
I guess that might provide some "empirical evidence" for the view that people tend to repent from suicide, to the extent that such evidence can even exist in the first place.
