I once saw an intriguing headline stating that using illegal drugs lead to lead poisoning, but was disappointed that the article was about contamination of the illicit supply and pot metal vapes.
It'd be interesting to see per-drug statistics for postmortem drug screening, nationwide and regionally.
There was a period around the late 80s through 1990's where NYC reported that these tests showed between
a third and half of homicide victims tested positive for cocaine (metabolites), and
only slightly lower across the total cadre of untimely deaths in NYC. I thought this was odd, so I asked around, and the best guess I heard for causation was
"cokeheads are dicks to everybody; of course they got themselves shot"
While I'd expect using marijuana would have the opposite effect, the few studies I could find showed a slight positive correlation -- homicide victims are about as likely to use pot as their peers (the slightly higher rate perhaps being related to THC's inhibition of impulse control?).