You may want to look at the ICD 10 criteria:

A cluster of physiological, behavioural, and cognitive phenomena in which the use of

a substance or a class of substances takes on a much higher priority for a given

individual than other behaviours that once had greater value. A central descriptive

characteristic of the dependence syndrome is the desire (often strong, sometimes

overpowering) to take psychoactive drugs (which may or may not have been

medically prescribed), alcohol, or tobacco. There may be evidence that return to

substance use after a period of abstinence leads to a more rapid reappearance of other

features of the syndrome than occurs with nondependent individuals.

Diagnostic guidelines

A definite diagnosis of dependence should usually be made only if three or more of

the following have been present together at some time during the previous year:

(a) a strong desire or sense of compulsion to take the substance;

(b) difficulties in controlling substance-taking behaviour in terms of its onset,

termination, or levels of use;

(c) a physiological withdrawal state (see F1

x.3 and F1x.4) when substance use hasceased or been reduced, as evidenced by: the characteristic withdrawal syndrome

for the substance; or use of the same (or a closely related) substance with the

intention of relieving or avoiding withdrawal symptoms;

(d) evidence of tolerance, such that increased doses of the psychoactive substances

are required in order to achieve effects originally produced by lower doses (clear

examples of this are found in alcohol- and opiate-dependent individuals who may

take daily doses sufficient to incapacitate or kill nontolerant users);

(e) progressive neglect of alternative pleasures or interests because of psychoactive

substance use, increased amount of time necessary to obtain or take the substance

or to recover from its effects;

(f) persisting with substance use despite clear evidence of overtly harmful

consequences, such as harm to the liver through excessive drinking, depressive

mood states consequent to periods of heavy substance use, or drug-related

impairment of cognitive functioning; efforts should be made to determine that the

user was actually, or could be expected to be, aware of the nature and extent of

the harm.

This is what I found.:

WHO | Dependence syndromewww.who.int/substance_abuse/terminology/definition1/en

Best regards

Jutta Eschle

recently we published a paper for debate about problems with the definition. You may want to have a look at it.

Best

Article Defining Substance Use Disorders: Do We Really Need More Tha...

Article The Tangible Common Denominator of Substance Use Disorders: ...

Here is the short definition from American Society of Addiction Medicine (highly credible), rewriten in 2011 and considering addiction as a brain chronic illness.

"Addiction is a primary, chronic disease of brain reward, motivation, memory and related circuitry. Dysfunction in these circuits leads to characteristic biological, psychological, social and spiritual manifestations. This is reflected in an individual pathologically pursuing reward and/or relief by substance use and other behaviors.

Addiction is characterized by inability to consistently abstain, impairment in behavioral control, craving, diminished recognition of significant problems with one’s behaviors and interpersonal relationships, and a dysfunctional emotional response. Like other chronic diseases, addiction often involves cycles of relapse and remission. Without treatment or engagement in recovery activities, addiction is progressive and can result in disability or premature death."

If you are interested, I suggest you look at the long definition. Many interesting points of view from neurobiology and genetic. Here's the link.

Best regards

(sorry for any syntaxic error, english isn't my first language :))

http://www.asam.org/for-the-public/definition-of-addiction

In my opinion, the most-known medical definition is Goodman's one: Br J Addict 1990; 85(11):1403-8.

Please also have a look at a very interesting letter exchange published in the Am J Psychiatry in 2006: http://www.ncbi.nlm.nih.gov/pubmed/16648309

Sincerely

Here is the WHO definition available in their lexicon of terms associated with drug and alcohol abuse:

addiction, drug or alcohol:  Repeated use of a psychoactive substance or substances, to the extent that the user (referred to as an addict) is periodically or chronically intoxicated, shows a compulsion to take the preferred substance (or substances), has great difficulty in voluntarily ceasing or modifying substance use, and exhibits determination to obtain psychoactive substances by almost any means. Typically, tolerance is prominent and a withdrawal syndrome frequently occurs when substance use is interrupted. The life of the addict may be dominated by substance use to the virtual exclusion of all other activities and responsibilities. The term addiction also conveys the sense that such substance use has a detrimental effect on society, as well as on the individual; when applied to the use of alcohol, it is equivalent to alcoholism. Addiction is a term of long-standing and variable usage. It is regarded by many as a discrete disease entity, a debilitating disorder rooted in the pharmacological effects of the drug, which is remorselessly progressive. From the 1920s to the 1960s attempts were made to differentiate between addiction ; and "habituation", a less severe form of psychological adaptation. In the 1960s the World Health Organization recommended that both terms be abandoned in favour of dependence, which can exist in various degrees of severity. Addiction is not a diagnostic term in ICD-10, but continues to be very widely employed by professionals and the general public alike. See also: dependence; dependence syndrome

I like the NIH definition:

Addiction is defined as a chronic, relapsing brain disease that is characterized by compulsive drug seeking and use, despite harmful consequences. It is considered a brain disease because drugs change the brain; they change its structure and how it works. These brain changes can be long lasting and can lead to many harmful, often self-destructive, behaviors.

I like the NIH definition too, although I think it doesn't capture the whole concept and implicitly leaves out behavioral addictions (sex, gambling, etc).  Am I right in concluding there is no MEDICAL CONSENSUS on the definition of addiction, thus no Dx (in either DSM or ICD) of "addiction" per se?  (there is no such thing as "substance use disorder - generalized" either, rather each "use disorder" is broken down by substance, such as opioid use disorder (304.xx) etc...  This is somewhat frustrating, but perhaps also reflects (a) poor understanding of the neurobiology/neuropsychology of addiction (b) the need for a context-sensitive definition - e.g. in some cases dependence may be more important than compulsive use, etc (c) just the lack of data on patients and (d) a completely underdeveloped sense of the etiology of addiction.  Should we stop using the term since nobody really agrees on what it means, or is it a "I know it when I see it" sort of concept?