The drugs that are causing the most deaths are synthetics, such as oxycodone. Fentanyl is often mixed with heroin and is extremely hazardous, even to touch. Heroin comes from a handful of sources, with Afghanistan being the largest producer. (Maybe that's why we are there...to protect the crops.) The abuse comes from stupidity of the users and greed of the pharmaceutical industry.
I think stupid/careless/greedy doctors have a hand in it, too. They should be held accountable for off-label and over-prescribing.
Purdue Pharma, who has already made billions from opiates and opiate-overdose antidotes is now poised to cash in on treatment for the addictions they helped create. https://www.vox.com/science-and-health/2018/9/7/17831710/richard-sackler-opioid-epidemic-buprenorphine
I was addicted to prescription narcotics for years - but they exist (and were prescribed for me by a physician I still trust) for a valid medical reason - analgesia from extreme, chronic pain. The source of the pain has been surgically corrected and I no longer need the opioids. There are those who become addicted who never needed them. Those are the abusers.
Addiction is one thing, abuse is another. Not every addict started out as a legitimate user of a properly-prescribed drug, not every abuser gets the drug of choice from legitimate sources. ~
Element 99 