|A cluster of physiological, behavioural, and cognitive phenomena in which the use of opioid 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 opioid (which may or may not have been medically prescribed). 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.|
A definite diagnosis of dependence should usually be made only if three or more of the following have been experienced or exhibited at some time during the previous year:
(a) a strong desire or sense of compulsion to take opioid;
(b) difficulties in controlling opioid-taking behaviour in terms of its onset, termination, or levels of use;
(c) a physiological withdrawal state when opioid use has ceased or been reduced, as evidenced by: the characteristic withdrawal syndrome for opioid; 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 opioid are required in order to achieve effects originally produced by lower doses (clear examples of this are found in 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 opioid use, increased amount of time necessary to obtain or take the substance or to recover from its effects;
(f) persisting with opioid use despite clear evidence of overtly harmful consequences, such as 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.
Narrowing of the personal repertoire of patterns of opioid use has also been described as a characteristic feature.
It is an essential characteristic of the dependence syndrome that either opioid taking or a desire to take opioid should be present; the subjective awareness of compulsion to use drugs is most commonly seen during attempts to stop or control substance use. This diagnostic requirement would exclude, for instance, surgical patients given opioid drugs for the relief of pain, who may show signs of an opioid withdrawal state when drugs are not given but who have no desire to continue taking drugs.