Although addiction is in DSM-V and it's nearly unavoidable to discuss in this case, IMO. Addiction is mental illness in my opinion (former professor at UCLA's Neuropsychiatric Institute). Anyway, I won't discuss it further, but I will add that he sounds like what we called a Weekend Warrior (mostly professionals in one of our studies, btw - mostly doctors). When they need lots of energy, they don't use. But they need to come down sometime and rest. I'm trying to avoid most DSM labels - but addiction is right there in the book.
The DSM 5 has eleven criteria for substance use disorders based on decades of research.The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, or DSM-5, is the American Psychiatric Association’s goldstandard text on mental health that was crafted by hundreds of mental health...
www.addictionpolicy.org