I have Renal failure TDM. I would be quite happy to have a fentanyl, alcoholic, or nicotine addict kidney transplant, thank you very much. 

You tried to limit this discussion to severe addicts only. 

Many of the substance abusers who OD on fentanyl, or survive with severe permanent brain damage, are so called "casual" abusers. 

Some people say that pot is not addictive, but my oldest brother is an example of over 4 decades of pot abuse and social dysfunction. He and his harder drug using girlfriend had to be evicted from our mother's home at age 60, for physical and financial elder abuse. 

I don't think it ever occurred to pot head that an overage stoner living in his mother's basement is a Hollywood Comedy stereotype. That "joke" did not seem so funny in Real Life, particularly when it involves raiding mother's Reverse Mortgate to support his and his girlfriend's substance abuse, and punching her. RCMP told the girlfriend to leave, then we got a no contact order.