A relapse happens when a person stops maintaining his or her goal of reducing or avoiding use of alcohol or other drugs and returns to previous levels of use. Recovering from a dependence on alcohol or another drug is a process that can take time. A relapse (or multiple relapses) is one part of recovering from alcohol and other drug dependence and can often be a feature of the recovery... (Alcohol and Drug Foundation).

Relapse-prevention cognitive behavioural therapy - This differs from standard cognitive behavioural therapy in the emphasis on training drug users to develop skills to identify situations or states where they are most vulnerable to drug use, to avoid high-risk situations, and to use a range of cognitive and behavioural strategies to cope effectively with these situations (Drug Misuse: Psychosocial Interventions glossary)

• Relapse prevention: A set of therapeutic procedures employed in case of alcohol or other drug problems to help individuals avoid or cope with lapses or relapses to uncontrolled substance use. The procedures may be used with treatment based on either moderation or abstinence, and in conjunction with other therapeutic approaches. Patients are taught coping strategies that can be used to avoid situations considered dangerous precipitants of relapse, and shown, through mental rehearsal and other techniques, how to minimize substance use once a slip has occurred (WHO lexicon).

Recurrence - The return of a sign, symptom, or disease after a remission. (Pubmed MESH)