I don't know about medical, but in psychology something is considered an illness/abnormality if it affects your ability to cope with a normal life, and a dependency on a substance like alcohol or heroin or valium where you would have trouble coping without it would be part of that (and no smartarse comments about "I'm dependent on oxygen/water/food" please). Could you manage a month without alcohol? Or would you get to some point in the first week or so and be going "bloody hell, I *need* a drink..." If you can't go without alcohol for a month, then you're looking down the slope of alcoholism if not already sliding your way down it. People I know who have tried it have either done it, no problem, and found that success reassuring - or they had trouble doing it, and it gave them the wake-up call that they really were dependent on alcohol and so they started making an effort to get it sorted out before they did their bodies and relationships permanent damage. And I know a lot of people will go "oh but I don't think ANY of my mates could go a month without alcohol", all that would mean would be that addiction is the norm for that group.