I'm not a doctor, and this is only anecdotal, but...
... when one of my alcoholic friends died (in an accident), the autopsy revealed a blood alcohol content that (the autopsy report said) would have killed a normal person. The fact that my friend wasn't just conscious, but upright and skateboarding, with that BAC, the report interpreted as him being an alcoholic. I know it took more and more alcohol for him to reach the level of intoxication he was aiming for.
And yet, none of us back then thought of him as an alcoholic. He just drank a lot...