A mindfulness-based smoking cessation app may help reduce smokers’ daily cigarette consumption — especially for women — and may change brain activity in the posterior cingulate cortex (PCC), a region implicated in cravings, new research suggests.
Investigators compared the mindfulness training (MT) app to a smoking cessation app from the National Cancer Institute (NCI) over a 1-month period and found that among those who used the MT app, there was a significant correlation between a reduction in PCC reactivity to smoking cues and a decline in cigarette consumption that was not found in the control group.
The investigators also found an association between the daily reduction in the number of cigarettes smoked and the number of MT modules the participant completed.
“The take-home message is that this is the first study to link brain mechanisms to clinical outcomes, showing that there is a very specific mechanism of how mindfulness words,” senior author Judson A. Brewer, MD, PhD, associate professor of psychiatry, Warren Alpert Medical School of Brown University, and director of research and innovation, Brown University Mindfulness Center, Rhode Island, told Medscape Medical News.
“If we can understand basic mechanisms of how mindfulness works — both behavioral and neurological — it could usher in a new wave of treatment that can specifically target brain regions involved in getting caught up in cravings and get good efficacy and long-lasting effects where other treatments might fail,” he said.
Although several regions of the brain have been implicated in cigarette cue-reactivity, the PCC, “a major node of the default mode network (DMN), has come into focus,” the authors write.
This is the area of the brain responsible for self-reference as well as cue-reactivity in addictive disorders, they continue.
The authors note that “increased PCC activity has been suggested to be associated with ‘getting caught up’ in one’s experience, such as getting fixated on a particular thought, lost in mind-wandering, or pulled into drug craving.”
However, the PCC can become deactivated during “non-self-referential tasks,” of which mindfulness meditation is an example.
Previous research has found that engaging in mindfulness can decrease PCC activity in experienced meditators and that MT can moderate a “decoupling of cue-induced craving and smoking, suggesting an extinction of operantly conditioned habits,” the investigators note.
App-based smartphone interventions have shown increasing utility in delivering behavioral treatments, the authors observe.
This new class of “digital therapeutics” may therefore be an effective way of delivering MT.
“Mindfulness has been pretty popular in the last couple of years, but it’s been unclear what mechanisms are around why it helps people change habits,” Brewer said.
To investigate the neurobiologic effects of MT delivered via an app on smoking cue-reactivity in the PCC, the researchers compared 33 smokers who received smartphone app–based MT to 34 active control persons who used the NCI’s app-based QuitGuide .
The MT program delivered the “core elements” of a manualized MT program for smoking cessation with “high fidelity.”
The MT program, which is publicly available for free, consists of 22 “unique learning modules.” Each module contains daily training videos and in vivo on-demand exercises and take 5 to 15 minutes to complete.
The various components of the program “are designed to help users self-monitor their smoking habits, identify triggers for smoking, learn methods to become more aware of cravings, and use mindfulness practices to ride them out,” the authors state.
Brewer noted that the program is set up so that people do not “binge watch, because learning doesn’t happen that way.”
The primary outcome of the study was “to demonstrate that app-based MT reliably decreased PCC reactivity to smoking cues,” the authors state.
Participants were required to be smoking >10 cigarettes/day, to have had <3 months of smoking abstinence in the previous year, to have scored >8 of 10 on a readiness-to-change scale, to own a smartphone, and to be 21 to 65 years old.
Exclusion criteria included a history of neurologic or psychiatric conditions, previous experience with mindfulness-based stress reduction, current meditation or yoga practice, current alcohol abuse, pregnancy, or MRI incompatibility.
The researchers calculated changes in cigarette use and change in PCC activity (Δ) by subtracting baseline from posttreatment values.
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Participants performed a smoking cue-reactivity fMRI task at baseline and were then randomly assigned to either the MT or the active control app.
They were instructed to use their app to help them quit smoking over the next 4 weeks. At a posttreatment visit, they completed the same cue-reactivity task that they had completed at baseline.
The researchers assessed smoking status with a carbon monoxide breathalyzer test at each visit.
Immediately prior to each MRI visit, participants smoked so as to reduce variability related to cravings during the MRI cue-reactivity task.
The task consisted of being shown 60 images involving smoking, 60 neutral images, and 10 target images during the MRI scan.
No differences were found in the expectancies of the MT and NCI groups at baseline regarding the participants’ perspectives on the usefulness of the app, their confidence in recommending the app to a friend, and their likeliness of quitting.
There were also no differences between the groups in number of modules completed.
However, at follow-up, the MT group reported a significantly higher likelihood of recommending the intervention to a friend, compared to the NCI group (9.6 ± 0.7 vs 5.9 ± 3.4, P < .001, d = 1.5).
At baseline, the number of cigarettes smoked by individuals in the MT and NCI groups was similar (16.8 ± 5.5 and 16.6 ± 5.9 cigarettes/day, respectively).
By contrast, at the postintervention assessment, participants in the MT and NCI groups reported smoking 5.4 ± 5.6 and 7.9 ± 8.0 cigarettes/day, respectively.
This translated into an average reduction of 11.4 ± 7.4 (P < .0001, d = 2.05) in the MT group and 8.7 ± 5.8 (P < .0001, d = 1.28) cigarettes/day in the NCI group.
More Effective in Women
A significant correlation was found in the MT group vs the MCI group between the number of training modules that an individual completed and the change in number of cigarettes smoked/day (r S = 0.49, P = .004; and r S = .20, P = .25, respectively).
No between-group difference in pre- vs posttreatment PCC cue-reactivity was found when the differences were directly compared (MT: −3.6 ± 33.9 [95% confidence interval (CI) = 12.0] vs NCI: −2.77 ± 33.0, [95% CI = 11.5]; P = .92, d = .02).
A significant correlation was found between reduction in PCC reactivity and the change in number of cigarettes smoked/day in the MT group (r = 0.39, P = .02,), but no similar correlation was found in the NCI group (r S = .08, P = .65).
In a linear regression model that combined ΔPCC, number of modules completed, and cigarettes smoked at baseline, all predictors were significantly related to the change in cigarette smoking for the MT group. There was a decrease of 0.07, 0.30, and 0.75 cigarettes/day smoked for every unit decrease in the PCC, every module viewed, and every cigarette smoked at baseline, respectively (R 2 = .58).
Conversely, for the NCI group, no predictors were associated with changes in cigarette smoking (R 2 = .08).
A post hoc evaluation regarding the sex of the participants showed that the ΔPCC correlation with the change in number of cigarettes smoked/day was significant in women but not in men who received MT (r S = 0.49, P = .03; and r S = −0.08, P = .79, respectively).
By contrast, no similar association was observed in the NCI group, even when women and men were evaluated independently.
“What we found was that reduction in PCC activity predicted reductions in cigarette smoking specific to the MT group,” Brewer reported.
The authors add, “The current finding fits with the theoretical framework that men and women smoke for different reasons and mitigating a PCC-mediated internal focus is more strongly linked with a reduction in smoking in women.”
Commenting on the study for Medscape Medical News, Linda E. Carlson, PhD, RPsych, Enbridge Research Chair in Psychosocial Oncology and professor, Department of Oncology, Cumming School of Medicine, who was not involved with the study, noted that the app “was not effective overall for reducing smoking or changing brain responses to smoking cues.”
However, “when changes were looked at within the app training group, there were associations between app use, reduction in brain activation to smoking cues which trigger cravings and actual smoking behavior, and largely this held only for women,” she said.
“This study suggests that apps and other interventions which target reductions in responses to smoking cues…may be effective in helping women in particular cut down on [cigarette] consumption,” she said.
Carlson, who is also adjunct professor in the Department of Psychology, University of Calgary, Canada, cautioned that the results are observational and do not reflect causation, “so much more definitive work needs to be done to address these possibilities.”
The authors suggest that their work “supports the hypothesis that mindfulness training reduces PCC reactivity to smoking” and may provide a “neurobiological mechanism for its effectiveness and potential biotype markers that can be assessed for personalization and optimization of treatment and resultant clinical outcomes.”
The study was supported by grants from the National Center for Complementary and Integrative Health and the National Institute on Drug Abuse. Brewer is the founder of MindSciences, the company that developed the mindfulness app used in this study, and owns stock in the company, serves as a noncompensated scientist for the company, and has previously served on the board of directors. The other study authors have disclosed no relevant financial relationships. Carlson receives royalties for two books about mindfulness and an online mindfulness-based cancer recovery program.
Neuropsychopharmacology. Published online April 30, 2019. Abstract