Neural Basis of Smoking-Related Difficulties in Emotion Regulation

Abstract

Background: Negative emotional states contribute to cigarette smoking, and difficulties in regulating these states can hinder smoking cessation. Understanding the neural bases of these difficulties in smokers may facilitate development of novel therapies for Tobacco Use Disorder.

Methods: Thirty-seven participants (18 smokers, 19 nonsmokers; 16-21 years old) completed the Difficulties in Emotion Regulation Scale (DERS), which is comprised of 6 subscales (lack of emotional clarity, lack of emotional awareness, limited access to emotion regulation strategies, nonacceptance of emotional responses, difficulties engaging in goal-directed behaviors, and impulse control difficulties) that combine to provide a total score. Participants also underwent functional magnetic resonance imaging to determine resting-state functional connectivity of the amygdala. Separate ANOVAs were used to determine group differences in self-reports on the DERS. Voxel-wise linear mixed models were performed to determine whether group influenced relationships between whole-brain functional connectivity of the amygdala and scores on the DERS.

Results: Compared with nonsmokers, smokers reported greater difficulties in emotion regulation, denoted by higher total scores on the DERS. Group differences were observed on a subscale of lack of emotional clarity, but no other subscale differences on the DERS were observed. Nonsmokers exhibited a greater negative correlation than smokers between lack of emotional clarity scores and connectivity of the amygdala with the left inferior frontal gyrus. Finally, this amygdala-to-left inferior frontal gyrus connectivity was weaker in smokers than in nonsmokers.

Conclusions: These findings suggest that difficulties in emotion regulation in smokers are at least partially due to lack of emotional clarity. Given the role of the inferior frontal gyrus in understanding emotional states, strengthening connectivity between the amygdala and the inferior frontal gyrus may improve emotional clarity to help smokers regulate their negative emotions, thereby improving their ability to quit smoking.

Keywords: Smoking; amygdala; emotion regulation; fMRI; inferior frontal gyrus.

Figure 1.

Group differences in Difficulties in Emotion Regulation Scale (DERS) total scores (A) and in scores from the lack of emotional clarity subscale (B). Asterisk in (B) denotes the Bonferroni-corrected P value.

Figure 2.

Effect of group on the relationship between resting-state functional connectivity and scores from the lack of emotional clarity subscale of the Difficulties in Emotion Regulation Scale (DERS). (A) Cluster denotes the region in which connectivity with the bilateral amygdala is more associated with a lack of emotional clarity in smokers than in nonsmokers. (B) Correlation of scores from the lack of emotional clarity subscale and z values from the cluster depicted in Figure 2A. (C) Graph depicts mean z values from the clusters shown in Figure 2A, for smokers and nonsmokers separately.