Addiction is diagnosed based on phenomenology, characterized by patterns of behavior including the four C's (out of control use, compulsive use, cravings, continued use despite consequences) plus tolerance and withdrawal.

“so the diagnosis of addiction is based on what we call phenomenology these are patterns of behavior that repeat themselves across individuals with unique temperaments demographics time periods Geographic locations um there is no brain scan or blood test to diagnose addiction although we know that addiction is characterized by distinct brain changes we're just not at a state-of-the-art where we can diagnose it based on that so it's still based on patterns of behavior that can broadly be summarized as the four C's plus tolerance and withdrawal”