Maybe he was in recovery before he ever finished medical school - like maybe he had done some kind of performance-enhancing something at USC and had a change of heart, so came back to the Caribe to finish med school.
Just thinking out loud here, but we don’t know that it happened after he was a doctor. Although, it would explain his going from “psychiatrist” to “psychologist” but would not explain his treating ANS as an MD/psych.
Quite possible. He may very well be an excellent addiction specialist, as you almost have to have been a past addict to be especially good and effective at being a rehab counselor or something related. Not saying all who study addictive behaviours and go into a line of work or research dealing with substance abuse or addiction issues have been addicts, because they’re not. I know of a couple, one is a family therapist and the other a psychiatrist, who are good at dealing with clients and patients with these problems.