I read in my research about manic depression that the only effective medication for Depression is vitamin D i.e. SUNSHINE. I have demonstrated that for half a dozen people who were either manic depressive or stuck in a deteriorating long term depression. One surprised me a year after I got her started taking D3 supplements. Her whole persona had changed in the year since I had last seen her and she was a happy person and she told me that she had quit taking Methadone. That was a shock to me that she had been a heroin addict until I thought about it. Horse addicts are mostly if not all night people and rarely experience sunshine- vitamin D. They are depressed and the H keeps them depressed but numb. Sunshine is thus probably an effective treatment for Heroin and perhaps opioid addiction. I am just speculating about that, especially about the opioid part but it seems likely to me.
We had horses and got a lot of sunshine while riding. Although we spent a lot of time with them I don’t know if that would be considered addicted to horses.