My addict's DOC was meth.
When it went on long enough, she became full on psychotic.
After 15 years of addiction, felonies, incarceration, rehab, relapse, repeat, what brought sanity to my life was letting go and letting be - she's sober and in a group home (at least for now).
So, yes, it is a hell of a drug, and it is a choice. There is help for addicts when they are ready to put in the work.
And, for those of us who love them - it is important to be vigilant to our "hooks" - the things that make us do crazy things for them that don't really help. It amazes me how little I was willing to treat her like an adult who needed to learn from the consequences of her choices - when that was the only thing that made a different. So good for you that you are doing something for yourself after only 3 years.
Wishing you clarity and courage.