• An alcohol problem is based on the level and pattern of alcohol consumption — categorized into hazardous drinking, harmful drinking, and alcohol dependence. This is based on the World Health Organization (WHO) International Statistical Classification of Diseases and Related Health Problems, tenth revision (ICD-10), categorization of alcohol-use disorders.
• Hazardous drinking is drinking above safer drinking limits. However, the person has so far avoided significant alcohol-related problems.
• Binge drinking is defined as drinking over twice the recommended units of alcohol per day in one session. This is considered more than 8 units for men or more than 6 units for women.
• Harmful drinking is drinking above safe levels (usually beyond those of hazardous drinking) with evidence of alcohol-related problems. These people may show a mild level of dependence (even if it is only an importance of alcohol in their lifestyle).
• Alcohol dependence is defined in ICD-10 as a cluster of physiological, behavioural, and cognitive phenomena in which the use of alcohol takes on a much higher priority for a given individual than other behaviours [WHO, 1992]:
• A central characteristic is the desire to drink alcohol, and a return to drinking after a period of abstinence, is often associated with a reappearance of the features of the syndrome (priming) [SIGN, 2003].
• A definite diagnosis of dependence is usually made only if three (or more) of the ICD-10 criteria for alcohol dependence are satisfied (see Alcohol dependence) [SIGN, 2003]. These people are considered to have a moderate to severe dependence on alcohol, although a person with two features or fewer may have mild dependence.

[DH, 2006; Raistrick et al, 2006]