Abstinence-induced changes in self-report craving correlate with event-related FMRI responses to smoking cues

Abstract

Drug cues have been shown to activate brain regions involved in attention, motivation, and reward in addicted users. However, as studies have typically measured responses in only one state (ie drug abstinence), it is unclear whether observed activations represent amplification by abstinence or stable responses. Thus, the present study was designed to evaluate the stability of event-related responses to visual drug cues in dependent smokers (n=13) using event-related functional magnetic resonance imaging measures. Imaging was conducted following smoking as usual and following overnight abstinence, and self-reported craving measures were obtained before, during, and after scanning. Analysis of hemodynamic response (HDR) amplitudes in each of 13 regions of interest revealed larger responses to smoking compared to control cues in ventral anterior cingulate gyrus (vACG) and superior frontal gyrus. Responses to smoking cues in these and all other regions revealed no effects of abstinence/satiety, thus supporting the notion that cue-elicited brain responses are relatively stable. However, while the abstinence manipulation did not alter group-level responses to smoking cues, at the individual level, abstinence-induced changes in craving (abstinence minus satiety) were positively correlated with changes in HDR amplitude to smoking cues in frontal regions including left inferior frontal gyrus, left vACG, and bilateral middle frontal gyrus. These results suggest that brain responses to smoking cues, while relatively stable at the group level following short-term abstinence, may be modulated by individual differences in craving in response to abstinence-particularly in regions subserving attention and motivation.

Figure 1

Effects of overnight abstinence and time (prescanning vs postscanning) on mean withdrawal symptoms as measured by SWQ (Shiffman and Jarvik, 1976).

Figure 2

Group-averaged event-related HDRs to smoking and control cues following overnight abstinence (Abstinent) and smoking as usual (Satiated) in dependent smokers. Values are expressed as percent signal change from baseline for the following regions: IFG, MFG, SFG, ventral ACG (V-ACG), dorsal ACG (D-ACG), ventral striatum (V-STR), thalamus (THL), and insula (INS). ^aObserved effects of Session in MFG and Stimulus in V-STR were only marginally significant (see Table 1 for statistical information).

Figure 3

Relations between the effect of overnight abstinence on Shiffman–Jarvik short form Craving and HDRs to smoking cues in the left and right MFG. The effects of overnight abstinence were calculated by subtracting values obtained following smoking as usual from those obtained following overnight abstinence. Positive numbers reflect abstinence-induced increases in craving and larger response to smoking cues.