It takes a surprising amount of effort to kill a human body through these drugs. It's how their abuse got so popular in the first place, since their damage only becomes really apparent over decades of excess.

That would be an extreme case.

At the risk of stating the obvious, the reasoning for that sort of self-destructive lifestyle doesn't make sense on 2 fronts. First, living an extremely unhealthy lifestyle will of course shorten your life, exacerbating the tragedy that life is short / YOLO. Second, it will significantly degrade your quality of life during that time.