Effects of biochemical validation of self-reported cigarette smoking on treatment success and on misreporting abstinence.

Many investigators have reported that cigarette smokers who are trying to quit often falsely report being abstinent at the end of treatment. Unfortunately, much of the previous research designed to investigate this problem has been flawed, making the results difficult to interpret. We attempted to avoid these flaws and to investigate the measurement of alveolar carbon monoxide (CO) levels to validate self-reported smoking rates at the end of treatment. Participants in behavioral cessation clinics were randomly assigned to one of three conditions that varied in timing of exposure to information regarding CO measurement: at the beginning of treatment (demonstration of CO measurement, discussion of smoking effects on CO levels, and notification that individual CO levels would be measured at the conclusion of the clinic), at the end of treatment (demonstration, discussion, and notification of CO measurement prior to self-reports of smoking levels), or at the end of treatment (demonstration and discussion of CO measurement subsequent to self-reports of smoking levels). CO levels of all participants were measured at the end of treatment after they reported their current smoking levels. Only 16% of self-reports of abstinence were not verified by CO measurement. Smokers who observed the CO demonstration at the beginning of treatment were significantly more likely than the other two groups to achieve abstinence at the end of treatment and significantly less likely to misreport abstinence. Clinical and research implications of these results are discussed.