There is an interesting suicide poem, "Trouble" by Matthew Dickman, in the current The New Yorker. When one steps back and considers enough suicides, by different means in varying circumstances, it starts to seem dangerously anthropological in a way, as if suicide is just a behavior that self-conscious entities exhibit on occasion. People speculate about elephants and whales sometimes yielding voluntarily to death, but few things separate human beings from the rest of the animal world more starkly than suicide. Consciousness (or at least some neurological proclivity of which consciousness is an epiphenomenon) must have had major survival advantages over evolutionary time in order to outweigh suicide.
One alarming fact about psychiatry in the modern era (the past fifty years, when psychotropic medications have been more widely available) is the minimal impact on the suicide rate, which has hovered around 30,000 annually in the United Status for quite some time. Clearly there is much that we do not understand about suicide. Suicide has a grip on the social and historical imagination that far outweighs its actually impact on mortality; obviously one is much more likely to die of heart disease, cancer, or even an accident than from "self murder." In psychiatric practice it is striking to see the wide continuum of suicidal thinking and behavior. Of course, it is a truism that virtually all "normal" people occasionally have the thought of suicide cross their minds, particularly on a really bad day, but one useful boundarly marker of the grim realm of depression is a qualitatively different attitude toward suicide, which takes the form of a wan indifference to the attachments and rewards of life. Before one can pursue death one must first abandon life. As the conclusion of this poem suggests, this temptation must be resisted. Why? As every parent tells their children, "Just because."