Well, Polish people often overdo alcohol, a party without a bottle of voda (or five bottles) is not a party, teenagers also drink a lot. Unfortunately there are many alcoholics in the country.

I think, stereotypes can offend people, not only from Poland but from every country. So please read this or any official report about. http://www.worldatlas.com/articles/who-drinks-the-most-alcohol-consumption-by-country.html Personally I don't drink more than a glass of wine on some special occasions. Alcoholism or drug overuse is not the feature of nationality.