Shape of the relapse curve and long-term abstinence among untreated smokers.

OBJECTIVE: To describe the relapse curve and rate of long-term prolonged abstinence among smokers who try to quit without treatment.

METHOD: Systematic literature review.

DATA SOURCES: Cochrane Reviews, Dissertation Abstracts, Excerpt Medica, Medline, Psych Abstracts and US Center for Disease Control databases plus bibliographies of articles and requests of scientists.

STUDY SELECTION: Prospective studies of self-quitters or studies that included a no-treatment control group.

DATA EXTRACTION: Two reviewers independently extracted data in a non-blind manner.

DATA SYNTHESIS: The number of studies was too small and the data too heterogeneous for meta-analysis or other statistical techniques.

RESULTS: There is a paucity of studies reporting relapse curves of self-quitters. The existing eight relapse curves from two studies of self-quitters and five no-treatment control groups indicate most relapse occurs in the first 8 days. These relapse curves were heterogeneous even when the final outcome was made similar. In terms of prolonged abstinence rates, a prior summary of 10 self-quitting studies, two other studies of self-quitters and three no-treatment control groups indicate 3-5% of self-quitters achieve prolonged abstinence for 6-12 month after a given quit attempt.

CONCLUSIONS: More reports of relapse curves of self-quitters are needed. Smoking cessation interventions should focus on the first week of abstinence. Interventions that produce abstinence rates of 5-10% may be effective. Cessation studies should report relapse curves.