Also, some people are genetically predisposed to depression, and thus they may not appear to be undergoing any negative life experiences, yet still become depressed, and may die by suicide.
So, some people die by suicide because of a depression that was caused by genetics. You probably have heard about some indivuduals who died by suicide and did not exhibit any symptoms or appear to have any serious problems. In these cases, it is possible that the person had depression that occured because of this genetic factor.
It is very rare that someone dies by suicide because of one cause. Thus, there are usually several causes, and not just one, for suicide.
Many people die by suicide because depression is triggered by several negative life experiences, and the person does not receive treatment – or does not receive effective treatment – for the depression. (Some people need to go through several treatments until they find one that works for them.)