As has been found in previous studies [2
], 24 hours of cigarette deprivation produced generalized increases in craving, and immediate cigarette availability boosted craving reactivity to smoking related cues. Deprivation-enhanced craving was evident in multidimensional craving and nicotine withdrawal questionnaires administered just prior to the cue manipulation as well as on the craving measure given repeatedly during the cue-availability procedure. Despite the robust main effects for cigarette deprivation and availability, there was no consistent evidence that, even under conditions of immediate cigarette availability, deprivation selectively enhanced cue-induced craving.
In contrast to the common expectation that abstinence should sensitize cue-reactive craving, Powell and colleagues [26
] found that overnight cigarette abstinence reduced cue-reactive craving relative to a non-abstinent condition. In that study, cue-reactivity was indexed as a difference from baseline responding, a procedure that may provide a less sensitive assessment than measuring reactivity as response difference between drug cues and neutral cues [42
]. Indeed, a subsequent study from that same group [43
], in which cue reactivity was indexed as craving differences between smoking and neutral cues, found no evidence that abstinence moderated the magnitude of cue-reactive craving.
The finding that negative mood was elevated on cigarette trials relative to neutral cues parallels mood effects observed in conventional cue-reactivity studies in which smokers have no immediate access to cigarettes during cue exposures (see [44
] for review). The reversal of this pattern when cigarettes were immediately accessible replicates previous CAP findings [37
]. Thus, the mood ratings were sensitive to both the cue and availability manipulation but were not affected by cigarette deprivation. There also was no evidence in the mood ratings of any interactions between deprivation and cue reactivity or between deprivation and cigarette availability. That is, as with craving, there was no indication in mood report of any abstinence-induced sensitization to smoking cues.
The fact that both craving and positive mood increased with cigarette availability may suggest that smokers were expressing pleasure in anticipation of smoking [15
]; however, there was no evidence that positive mood was indexing the emotional valence of craving as there were no significant positive correlations between craving report and positive mood. An alternative hypothesis is that smokers were expressing relief that they could smoke on 100% probability cigarette trials and frustration when they knew they could not smoke or were uncertain of cigarette availability [37
]. The finding that positive correlations between negative mood and craving were significant at the 0% and 50% probability levels, but not at the 100% probability level, lends support to this interpretation. This pattern of mood results complements previous findings from other studies that negative mood, not positive mood, is most clearly linked with craving processes (see [44
] for review).
Although the self-report data did not support the predictions derived from several incentive motivational models of the impact of deprivation on reactivity to motivationally relevant cues, there was evidence in skin conductance responses of an interaction between abstinence and smoking cues. As has been observed in previous research [e.g., 19
], skin conductance responses were larger in the presence of cigarette cues relative to water cues. In addition, deprived smokers, but not non-deprived smokers, showed particularly strong skin conductance responses to cigarette cues on 100% availability trials. The magnitude of the difference in skin conductance responses between the Deprived and Non-Deprived groups on these trials was fairly robust (means of .32 and .13 μ-siemens, respectively), with an estimated effect size of .72 (Cohen's d
). To the best of our knowledge, the finding of increased skin conductance reactivity to smoking cues under conditions of cigarette deprivation has not been reported previously in the literature. This pattern, if replicated, suggests that skin conductance may offer unique information about motivational processes activated by smoking cues in a deprived condition. More generally, these divergent patterns across self-report and physiological measures illustrate that cue-reactivity responses are not uniform indices of a homogenous drug-motivational state. Indeed, the absence of significant correlations between skin conductance and self-reported craving suggest that these two measures of reactivity may be tracking somewhat independent processes.
We found that craving to smoke was significantly correlated with latency to access the door on both water and cigarette cue trials, but these relationships were restricted almost exclusively to smokers in the Deprived group. This finding parallels results reported by Sayette and colleagues [46
], who found that measures of craving-related processes were more strongly inter-related when smokers were abstinent from cigarettes for seven hours. A pattern of enhanced cohesiveness between craving and drug-use measures under conditions of cigarette deprivation is consistent with the proposal of Baker et al. [15
] that correlations between various manifestations of drug-motivational states should increase when drug-use motivation is strongest. In the current study, this pattern was not generalized across all craving correlates. That is, the relationships between mood measures and craving did not differ as a function of deprivation. Moreover, the correlations between craving and latency measures were not markedly affected by the cue-content of the exposure trials. These results indicate that, similar to the main effects of deprivation on craving, deprivation promoted greater cohesiveness among craving and certain other measures, but these correlations were not necessarily cue-specific.
When examining the impact of abstinence on craving reactivity, it is useful to employ procedures that maximize the possibility of detecting cue effects across a wide span of response levels. The CAP allowed for the assessment of craving responses across a range of stimulus intensities (i.e., availability), aggregated numerous cue trials at each level of cue type and availability, assessed craving directly in the presence of the cue, indexed craving reactivity relative to a neutral cue condition, and measured craving as the average of multiple items. Collectively, these features produced a craving assessment that was reliable, highly sensitive to cue manipulations, and not prone to ceiling effects that might have limited the detection of synergistic interactions between cue effects and abstinence. These considerations, in combination with the relatively large sample size used in this research, suggest that the absence of any enhanced reactivity to smoking cues under conditions of abstinence was not due to an insensitivity of craving assessment or lack of experimental power.
There are some limitations of this study that should be noted. Participants knew they could resume smoking immediately after the session and were only deprived of smoking for 24 hours. Smokers actively pursuing quitting and/or abstinent for a longer duration may show enhanced sensitivity to cigarette related stimuli. Nevertheless, it was clear from the self-report measures that the deprived smokers were experiencing symptoms of withdrawal and stronger craving than those in the non-deprived condition. Another factor that may have affected the results, particularly the lack of significant differences in heart rate between groups, is that smokers in the Deprived group were exposed to 12 puffs of a cigarette during the CAP. Although allowing people to smoke also could have affected craving levels, the amount smoked was equal to approximately one cigarette, a significantly lower amount than their typical smoking behavior. Furthermore, there were no significant block effects, suggesting that craving did not significantly change over the course of the session.
Our data are consistent with the hypothesis that deprivation and smoking cue presentations have independent, additive effects on craving levels in smokers. Beyond the conceptual implications for models of craving and drug-use motivation, these results have important ramifications for the assessment and treatment of craving. Several studies of the effects of transdermal nicotine patches on cue-elicited craving in smokers have shown that the nicotine patch had no significant impact on craving generated by smoking-related cues [28
]. Such results suggest that treatment may have to selectively target craving arising from cue-induced craving and deprivation-induced craving. More generally, the present data underscore the value of distinguishing between deprivation-induced and cue-induced craving for cigarettes [2