A lot of people do hard drugs - I've seen conservative estimates at ~12% of the of the adult and teenage population.
https://todaysveterinarynurse.com/practice-management/substa... which has these references (https://www.avma.org/javma-news/2015-09-15/putting-drug-test... was particularly useful). It sounds like, even with more access to abusable substances and stress than the general public, it is not wildly out of proportion to abuse rates of the general public.
1. Kahler SC. Putting Drug Testing Into Practice. avma.org/News/JAVMANews/Pages/150915e.aspx. Accessed July 15, 2019.
2. Geller J. Dark Shadows: Drug Abuse and Addiction in the Veterinary Workplace. veterinarynews.dvm360.com/dark-shadows-drug-abuse-and-addiction-veterinary-workplace?pageID=2. Accessed July 15, 2019.
3. Fishell SL. Signs and Symptoms of Possible Substance Use. cliniciansbrief.com/article/signs-symptoms-possible-substance-use. Accessed July 15, 2019.
4. How to Talk About Addiction. hazeldenbettyford.org/articles/what-can-i-say-to-get-you-to-stop. Accessed July 15, 2019.
5. Guidelines for Veterinary Prescription Drugs. avma.org/KB/Policies/Pages/Guidelines-for-Veterinary-Prescription-Drugs.aspx. Accessed July 15, 2019.
6. What to Do If Your Adult Friend or Loved One Has a Problem with Drugs. drugabuse.gov/related-topics/treatment/what-to-do-if-your-adult-friend-or-loved-one-has-problem-drugs. Accessed July 25, 2019.
Hard to believe it isn't widespread in the industry.
When challenged, you mention 4 vets you know. You say they've all at least experimented with animal drugs. What portion of the 4 said that was a reason for them to become vets? What portion did more than "at least experiment"? Do either of those represent a majority share of your sample? TBH, I think you would have phrased it differently if they did...
What is it about this small sample which is still influenced by your location, social class, education, etc that makes it representative of all vets?
Just wanted to note the wide gulf between your original reply and where you retreated.
also, ketamine has been shown to help with depression. could be that people are self-medicating.