Reversion to a pre-existing level of substance use and dependence in an individual who has resumed use following a period of abstinence. As described, not only does the individual return to the previous pattern of regular or intensive substance use, but there is also a rapid reinstatement of other dependence elements, such as impaired control, tolerance, and withdrawal symptoms. The term is used primarily in the phrase “rapid reinstatement”, which features in some descriptions of the alcohol dependence syndrome but is not included as a criterion in ICD-10.