Being labeled smart has a lot of drawbacks. It places a person on a pedestal, and if they take risks, they might fail, and lose the their smart status. Plus, when someone is gifted, they shouldn't have to work hard... right? Stupid people have to put effort into something. Or at least that is what's commonly understood.
Words like "addict," "abuser" and "alcoholic" are widely used indiscriminately to describe people who struggle with substance use issues and are laden with negative connotations for much of the culture. As a psychologist who treats substance use disorders I usually discourage my clients and their families from using these words to describe themselves or their loved one.