Opioid addiction is indeed a very big problem. And it goes far beyond street junkies, into college and middle class environments.
A common scenario begins with legitimate, prescribed opioid pain killers (Vicodin, Darvon, etc.).
But the prescription runs out, or the individual wants more, so they turn to street sources.
At the level of street sources, heroin is cheaper and easier to find.
So now you have a relatively inexperienced drug user, taking an unknown quantity of a deadly drug.
Janis Joplin and Jimi Hendrix didn't commit suicide. They overdosed when the drugs they got were far, far more potent than ordinary supplies.
Warren is correct, about researching to learn if marijuana could substitute for dangerous pain meds.