In support of this interpretation, we found no changes in overall craving selleck chem or withdrawal as smokers substituted Ariva/Stonewall for cigarettes, which is generally consistent with reports from others (Blank, Sams, Weaver, & Eissenberg, 2008; Kotlyar et al., 2007; Mendoza-Baumgart et al., 2007). However, although cigarettes per day significantly decreased among smokers who used Ariva/Stonewall, reduction in CO was less striking (6%), suggesting partial compensation (e.g., inhaling deeper, more frequent puffs) and/or problems with the use of CO as a biomarker of tobacco exposure in this population (see following). We found no evidence that smokeless tobacco (Ariva or Stonewall) undermines quitting.

To the contrary, readiness to quit (in the next 1 month and within the next 6 months) significantly increased among smokers who used a smokeless tobacco product relative to those who continued to smoke conventional cigarettes. No group differences were noted for stage of change movement. Confidence in quitting smoking also significantly increased within the smokeless tobacco group only. Each of these measures (readiness to quit and self-efficacy) is predictive of smoking cessation (Carpenter, Hughes, Solomon, & Callas, 2004; Gwaltney, Metrik, Kahler, & Shiffman, 2009). Thus, our data support the notion that Ariva or Stonewall, and perhaps smokeless tobacco in general, could serve as a catalyst to increase motivation among smokers not wanting to quit. This is consistent with the only published randomized clinical trial of smokeless tobacco among smokers wanting to quit (Tonnesen et al.

, 2008), which found mixed but generally supportive evidence that smokeless tobacco promotes cessation. The overall population impact of smokeless tobacco products, and PREPs in general, is unclear. Although PREPs are not yet popular among smokers, some indicators suggest they will be. Recent studies estimate that ever use of any PREP is between 4% and 10% but that consumer interest is much higher (50%�C77%; Hund et al., 2006; Parascandola, Hurd, & Augustson, 2008). Many smokers believe that these products are safer than conventional cigarettes (Biener et al., 2007; Hamilton et al., 2004; O��Connor et al., 2005). Thus, the allure of a ��safe(r)�� tobacco product offers intuitive appeal for many smokers, and it is likely that the product��s popularity will increase as palatability increases.

Within our study, palatability Brefeldin_A was mixed, and this may in part be a consequence of giving a smokeless tobacco product to cigarette smokers who are accustomed to the oral sensorimotor aspects of cigarette smoking. It is doubtful that a smokeless tobacco product could ever serve as a total substitute for cigarettes among a majority of smokers. However, the amount of substitution among those smokers who choose to use smokeless products is not insignificant.