I'm just going on how he's wording it. Overdosing (like a chain smoker), not getting help, dying from cancer caused from that, following his logic, would make you a suicide. In fact, that example would probably actually better qualify a person as a suicide in Stu's World as opposed to a person who OD'ed, as with smoking that usually takes years and years of knowingly engaging in that activity and feeling the ramifications of it over time and still continuing to do it, knowing what's happening. But all it takes is once from an overdose of pills, narcotics, etc, just one time. Never really be for sure (unless there's a note) if you were trying to kill yourself or you just miscalculated how much you were supposed to take.
See how ridiculous this gets?