Table 1 The main patterns of alcohol drinking

1 unit of alcohol contains 10 g of absolute ethanol [3].

PatternNumber of units/problems
Social drinkersUsually drink not more than 2–3 units of alcohol per day.
Hazardous drinkersDrink more than 1–2 units of alcohol/day (women) and more than 3–4 units/day (men). They are at risk of harm
Binge drinkersOccasionally drink more than 5 units of alcohol/day. The pattern is also called single occasion drinking
Heavy drinkersDrink regularly more than 6 units of alcohol/day. If immediate harm appears, they are called problem drinkers (also called harmful drinking or alcohol abuse)
Alcohol-dependent personsPeople that chronically drink alcohol. The most severe stage of drinking, with physical and psychological dependence. At least three of the following criterias are met: tolerance, withdrawal symptoms after cessation of drinking, impaired control, preoccupation with acquisition and/or use, persistent desire or unsuccessful efforts to quit, sustains social, occupational or recreational disability, and use continues despite adverse consequences