Specifically, a two-level model was fitted, where a level-1 submodel describes how each individual’s craving changed across 15 monitoring sessions over time and a level-2 selleck chemicals Imatinib Mesylate submodel relates interindividual differences in craving trajectories to predictors including individual genotypes, treatment, sex, the interaction of genotypes and treatment, the interaction of genotypes and sex, and other control personal variables such as age, FTND scores, and prequit craving levels. To obtain a more parsimonious representation from each multilevel model, level-2 fixed effect parameters that were not significant according to the single parameter hypothesis test (z-statistic but labeled as t ratio in HLM) or did not account for significant variance according to the model deviance statistic were removed sequentially from the initial model (for more details about this approach, see Supplementary Material and Gilbert et al.

, 2009). Because of statistical power limitations associated with the small sample size of the smoke group, we limited analysis at this step to the two abstinence groups (n = 129). Results Correlations between motivational measurements For each of the four categories of the SMOQ (cognitive enhancement, negative affect, pleasure, and weight control), subjects�� report of desire, probability, and motive for smoking was correlated at moderate to high levels (r = .56�C.87), indicating that desire, probability, and motive measure interrelated aspects of motivation to smoke. Overall, scores on the motive (reason) for smoking subscales of the SMOQ and similar measurements of the HWRSS were only modestly correlated.

There was a relatively high correlation (r = .37) between cognitive enhancement scores of the SMOQ and stimulation subscale scores of the HWRSS, suggesting that these two subscales capture on somewhat overlapping constructs. Cilengitide Similarly, ratings on the negative affect subscale of the SMOQ moderately correlated with the negative affect reduction subscale and the psychological addiction subscale of the HWRSS (r = .42 and .35, respectively). The latter could indicate a relatively closer association between smoking to cope with negative affect, among other reasons to smoke, and psychological addiction to smoking. As for craving measurements, prequit craving scores on the SWQ were modestly correlated with the four desire subscales on the SMOQ (r = .17�C.40). Among them, there was a relatively closer link between SWQ craving scores and desire for smoking as measured by the pleasure subscale of the SMOQ (r = .40). In short, these correlational results demonstrated that various measurements used in this study convergently measured both common and different motivations to smoke.