People who stop or limit their use of substances for whatever reason, often subsequently use substances again. This is partly why medical definitions of problem drug use talk of a chronic or relapsing condition (see addiction; see alcoholism). Relapse can take on significance too in some recovery discourses where a relapse to substance use means that people have to ‘start again’ in terms of their recovery. One symbol of this ‘starting again’ is that some people will start counting their days of abstinence from zero again (see clean).

Relapse is sometimes regarded in ways which may be potentially damaging. It may be unhelpful for people to think of relapse as inevitable. It may also be unhelpful for people to regard relapse as catastrophic or a clear break from a previous episode of controlled use or abstinence.

Relapse is for many people associated with a period where support is needed and this may help the person in the short and long term. Unfortunately, it is a time when support is often withdrawn by family, peer and other supports and also by some services.

Relapse is closely associated with an elevated risk of overdose including fatal overdose (see tolerance).