The commitment to quitting smoking scale: initial validation in a smoking cessation trial for heavy social drinkers.

We tested the psychometric properties and predictive validity of a newly developed 8-item measure of commitment to quitting smoking, conceptualized as the state of being personally bound or obligated to persist in quitting smoking despite potential difficulties, craving and discomfort. Participants were 157 heavy drinking smokers enrolled in a clinical trial of smoking cessation treatments. The measure showed strong unidimensionality, good internal consistency, and moderate stability from baseline to quit date. Commitment significantly increased from baseline to quit date. Higher commitment to quitting at baseline predicted greater odds of abstinence at post-treatment and 16 and 26 weeks after quit date. Commitment predicted smoking outcome over and above level of tobacco dependence, self-reported importance of quitting smoking, and self-efficacy for remaining abstinent. Results suggest that commitment is a highly relevant construct for smoking cessation, which can be reliably assessed with the Commitment to Quitting Smoking Scale and which may be an excellent target for smoking cessation treatments.