The first thing I did when I opened this article was search for "rat", and was happy to see it there. From the comments I saw I had a hunch it might be: I recently finished a really powerful chapter in the book "Chasing the Scream: The First and Last Days of the War on Drugs" which describes an experiment involving rats that ostensibly shows that addiction isn't about the chemical, but rather it's about the environme…
It definitely seems like a mix. I've been addicted (to the point of losing thousands and thousands) to gambling in the past - looking for a way out, something to change things financially - but alcohol or narcotic drugs did nothing for me. But I knew other people in the same situation whose relief came - more destructively, more difficult to recover from - from the drugs.
Ibogaine [1] has been found to be particularly effective in helping those suffering from addiction. Psilocybin has also seen research in this area with some positive results. [2]
[1] https://en.wikipedia.org/wiki/Ibogaine#Addiction_treatment