Neural stress reactivity relates to smoking outcomes and differentiates between mindfulness and cognitive-behavioral treatments

Abstract

Stress and negative affect are known contributors to drug use and relapse, and several known treatments for addictions include strategies for managing them. In the current study, we administered a well-established stress provocation during functional magnetic resonance imaging (fMRI) to 23 participants who completed either mindfulness training (MT; N=11) or the American Lung Association's Freedom From Smoking (FFS; N=12), which is a cognitive-behavioral treatment (CBT) for smoking cessation. Across the entire sample, we found that stress reactivity in several brain regions including the amygdala and anterior/mid insula was related to reductions in smoking after treatment, as well as at 3-month post-treatment follow-up. Moreover, conjunction analysis revealed that these same regions also differentiated between treatment groups such that the MT group showed lower stress-reactivity compared to the FFS/CBT group. This suggests that reduction in stress reactivity may be one of the mechanisms that underlie the efficacy of MT in reducing smoking over time. The findings have important implications for our understanding of stress, the neural and psychological mechanisms that underlie mindfulness-based treatments, and for smoking cessation treatments more broadly.

Trial registration: ClinicalTrials.gov NCT01144689.

Keywords: Stress; cognitive-behavioral therapy; fMRI; mindfulness; smoking.

Copyright © 2016 Elsevier Inc. All rights reserved.

Figures

Figure 1. Schematic Representation of Each Run

During each of 4 functional runs, participants first experienced a resting baseline for 30 seconds, and then heard the instruction “close your eyes and imagine the following situation as if it were happening right now.” Then, one of four individualized scenarios was played via headphones (two stressful/negative and two neutral/peaceful scenarios, presented in random order). Each scenario lasted 3 minutes, and was followed by the instruction “please stop imagining and lay still,” followed by a cooldown period. Before and after each run, participants rated their stress and craving on a 10-point scale; and after each scenario they rated the vividness of the imagined scenario.

Figure 2. Stress Reactivity: Comparison Between Treatment Groups

Neural activity during stressful scenarios was contrasted between the Freedom from Smoking (FFS) group and the Mindfulness Training (MT) group [FFSSTRESS>MTSTRESS]. The FFS group exhibited greater stress-related neural activity in left amygdala, anterior, middle, and posterior insula, and bilateral portions of parahippocampal gyrus and hippocampus, putamen, thalamus, midbrain and cerebellum (See Table 2A; See Supplementary Figures S5-S6 for full results). The MT group did not show greater neural reactivity in any region during stressful stories. Bar graphs represent the extracted cluster-averaged percent signal change in amygdala (top) and insula (bottom). Error bars represent standard errors. Results are familywise-error corrected (FWE) at p < .05. Left side of the brain is displayed on the left.

Figure 3. Stress Reactivity: Correlations with % Reduction in Smoking

Neural activity during stressful scenarios was correlated with % reduction in cigarettes per day from pre- to post-treatment (left scatter plots) and % reduction in cigarettes per day from pre-treatment to 3-month follow-up (right scatter plots). Full correlation results are displayed in Supplementary Figures S1–S4. A formal conjunction analysis between the two correlation maps revealed a set of regions that were responsive to stressful scenarios, and correlated with CPD reduction at both timepoints. Those included the left amygdala, extending into the anterior/mid insula (as shown here) and parahippocampal gyrus, as well as right hippocampus, parahippocampal gyrus, and posterior insula (shown in Supplementary Figure S7-S8). Scatter plots represent the extracted cluster-averaged percent signal change during stress scenarios in regions identified in the conjunction analysis.