Neural correlates of cigarette health warning avoidance among smokers

A meta-analysis of electrophysiological biomarkers of reward and error monitoring in substance misuse

Substance use disorders are characterized by marked changes in reward and error processing. The primary objective of this meta-analysis was to estimate effect sizes for the reward positivity (RewP) and error-related negativity (ERN), two event-related potential indicators of outcome monitoring, in substance users compared to controls. The secondary objective was to test for moderation by demographic, substance type, and EEG experiment parameters. Final PubMed searches were performed in August 2023. Inclusion criteria were substance use disorder/dependence or validated self-report of substance misuse, RewP/ERN means available, healthy control comparison group, non-acute drug study, peer-reviewed journal, English language, and human participants. Selection bias was tested through modified Egger's regression and exploratory 3-parameter selection model tests. The RewP results (19 studies, 1641 participants) did not support an overall effect (Hedges' g = 0.07, 95% CI [-0.44, 0.58], p = .777) and nor effect of any moderators. The ERN results (20 studies, 1022 participants) indicated no significant overall effect (g = 0.41, 95%CI [-0.05, 0.88]). Subgroup analyses indicated that cocaine users had a blunted ERN compared to controls (g = 1.12, 95%CI [0.77, 1.47]). There was limited evidence for publication/small study bias. Although the results indicate a potential dissociation between substance types, this meta-analysis revealed the need for additional research on the RewP/ERN in substance using populations and for better designed experiments that adequately address research questions.

Motivation to quit tobacco; Impact of different types of Anti-tobacco state-sponsored media propaganda messages

Introduction

Antitobacco media messages can easily reach the mass and play a very positive and significant role in changing the motivational stages among recent quitters. Motivation is the key to changing human behaviour. Motivation can be intrinsic and extrinsic. To modify tobacco-related behaviour, one must have an inherent motivation to quit tobacco. However, the outside factors, for example, protobacco advertisements, antitobacco advertisements, peer pressure, celebrity influence, and family members' influence cannot be ignored.

Method

A total of 400 recent tobacco quitters were enrolled from four colleges via a multistage sampling method. Time series research design was used for data collection at three time periods 0, 1, and 3 months. Study participants were divided into four groups: 1) personal testimony group, 2) health warning group, 3) celebrity-influenced public service announcements, and 4) natural exposure group. Media messages containing antitobacco video clippings and pictures were delivered to the participants via phone thrice a week, as per the groups assigned. All four groups were assessed for the motivational stage via contemplation ladder at 0, 1, and 3 months of intervals.

Results

Antitobacco personal testimonial media messages are most effective in enhancing the motivation to quit tobacco, followed by the antitobacco health warning messages, which are also proven to be effective in maintaining high motivation levels to remain abstinent from smoking. However, public service announcements are ineffective in keeping the motivation to quit tobacco at higher smoking.

Conclusion

Overall, the antitobacco state-sponsored media messages, personal testimonials, and health warnings about tobacco products effectively maintain and enhance motivation to quit tobacco.

Nudging Interventions on Alcohol and Tobacco Consumption in Adults: A Scoping Review of the Literature

Background: The World Health Organization identified alcohol and tobacco consumption as the risk factors with a greater attributable burden and number of deaths related to non-communicable diseases. A promising technique aimed to modify behavioral risk factors by redesigning the elements influencing the choice of people is nudging. Methodology: A scoping review of the literature was performed to map the literature evidence investigating the use of nudging for tobacco and alcohol consumption prevention and/or control in adults. Results: A total of 20 studies were included. The identified nudging categories were increasing salience of information or incentives (IS), default choices (DF), and providing feedback (PF). Almost three-quarters of the studies implementing IS and half of those implementing PF reported a success. Three-quarters of the studies using IS in conjunction with other interventions reported a success whereas more than half of the those with IS alone reported a success. The PF strategy performed better in multi-component interventions targeting alcohol consumption. Only one DF mono-component study addressing alcohol consumption reported a success. Conclusions: To achieve a higher impact, nudging should be integrated into comprehensive prevention policy frameworks, with dedicated education sessions for health professionals. In conclusion, nudge strategies for tobacco and alcohol consumption prevention in adults show promising results. Further research is needed to investigate the use of nudge strategies in socio-economically diverse groups and in young populations.

Late positive potential as a candidate biomarker of motivational relevance in substance use: Evidence from a meta-analysis

The objective of the current meta-analysis was to assess the effect size of the Late Positive Potential (LPP) to drug and emotional cues in substance users compared to controls. The secondary objective was to test for moderation by: age, gender, years of use, use status, and substance type. Search was performed in August 2021 using PubMed. Inclusion criteria were: substance use disorder/dependence or validated self-report, LPP means, healthy control comparison, non-acute drug study, data available, peer-reviewed journal, English, and human participants. Selection bias was tested through modified Egger's regression and exploratory 3-parameter selection model tests. Results (k = 11) indicated LPP to drug cues was larger in substance use compared to control group, with a large effect size (Hedges' g=1.66, 95%CI [0.64,2.67], p = 0.005). There were no overall differences for emotional cues. Though threats of selection bias were not severe, inclusion of more studies with larger sample sizes in future meta-analyses will allow more robust tests of publication bias and more accurate measures of effect size.

Standardised packs and larger health warnings: visual attention and perceptions among Colombian smokers and non-smokers

AIMS

To measure how cigarette packaging (standardised packaging and branded packaging) and health warning size affect visual attention and pack preferences among Colombian smokers and non-smokers.

DESIGN

To explore visual attention, we used an eye-tracking experiment where non-smokers, weekly smokers and daily smokers were shown cigarette packs varying in warning size (30%-pictorial on top of the text, 30%-pictorial and text side-by-side, 50%, 70%) and packaging (standardised packaging, branded packaging). We used a discrete choice experiment (DCE) to examine the impact of warning size, packaging and brand name on preferences to try, taste perceptions and perceptions of harm.

SETTING

Eye-tracking laboratory, Universidad Nacional de Colombia, Bogotá, Colombia.

PARTICIPANTS

Participants (n = 175) were 18 to 40 years old.

MEASUREMENTS

For the eye-tracking experiment, our primary outcome measure was the number of fixations toward the health warning compared with the branding. For the DCE, outcome measures were preferences to try, taste perceptions and harm perceptions.

FINDINGS

We observed greater visual attention to warning labels on standardised versus branded packages (F[3,167] = 22.87, P < 0.001) and when warnings were larger (F[9,161] = 147.17, P < 0.001); as warning size increased, the difference in visual attention to warnings between standardised and branded packaging decreased (F[9,161] = 4.44, P < 0.001). Non-smokers visually attended toward the warnings more than smokers, but as warning size increased these differences decreased (F[6,334] = 2.92, P = 0.009). For the DCE, conditional trials showed that increasing the warning size from 30% to 70% reduced preferences to try (odds ratio [OR] = 0.48, 95% CI = [0.42,0.54], P < 0.001), taste perceptions (OR = 0.61, 95% CI = [0.54,0.68], P < 0.001); and increased harm perceptions (OR = 0.78, 95% CI = [0.76,0.80], P < 0.001). Compared with branded packaging, standardised packaging reduced our DCE outcome measures with ORs ranging from OR = 0.25 (95% CI = [0.17,0.38], P < 0.001) to OR = 0.79 (95% CI = [0.67,0.93], P < 0.001) across two brands. These effects were more pronounced among non-smokers, males and younger participants. Unconditional trials showed similar results.

CONCLUSIONS

Standardised cigarette packaging and larger health warnings appear to decrease positive pack perceptions and have the potential to reduce the demand for cigarette products in Colombia.

Avoidance of tobacco health warnings? An eye-tracking approach

AIMS

Among three eye-tracking studies, we examined how cigarette pack features affected visual attention and self-reported avoidance of and reactance to warnings.

DESIGN

Study 1: smoking status × warning immediacy (short-term versus long-term health consequences) × warning location (top versus bottom of pack). Study 2: smoking status × warning framing (gain-framed versus loss-framed) × warning format (text-only versus pictorial). Study 3: smoking status × warning severity (highly severe versus moderately severe consequences of smoking).

SETTING

University of Bristol, UK, eye-tracking laboratory.

PARTICIPANTS

Study 1: non-smokers (n = 25), weekly smokers (n = 25) and daily smokers (n = 25). Study 2: non-smokers (n = 37), smokers contemplating quitting (n = 37) and smokers not contemplating quitting (n = 43). Study 3: non-smokers (n = 27), weekly smokers (n = 26) and daily smokers (n = 26).

MEASUREMENTS

For all studies: visual attention, measured as the ratio of the number of fixations to the warning versus the branding, self-reported predicted avoidance of and reactance to warnings and for study 3, effect of warning on quitting motivation.

FINDINGS

Study 1: greater self-reported avoidance [mean difference (MD) = 1.14; 95% confidence interval (CI) = 0.94, 1.35, P < 0.001, ηp2  = 0.64] and visual attention (MD = 0.89, 95% CI = 0.09, 1.68, P = 0.03, ηp2  = 0.06) to long-term warnings, but not for reactance (MD = 0.14, 95% CI = -0.04, 0.32, P = 0.12, ηp2  = 0.03). Increased visual attention to warnings on the upper versus lower half of the pack (MD = 1.8; 95% CI = 0.33, 3.26, P = 0.02, ηp2  = 0.08). Study 2: higher self-reported avoidance of (MD = 0.70; 95% CI = 0.59,0.80, P < 0.001, ηp2  = 0.61) and reactance to (MD = 0.37; 95% CI = 0.27, 0.47, P < 0.001, ηp2  = 0.34) loss-framed warnings but little evidence of a difference for visual attention (MD = 0.52; 95% CI = -0.54, 1.58, P = 0.30, ηp2  = 0.01). Greater visual attention, avoidance and reactance to pictorial versus text-only warnings (all Ps < 0.001, ηp2  > 0.25). Study 3: greater self-reported avoidance of (MD = 0.37; 95% CI = 0.25, 0.48, P < 0.001, ηp2  = 0.33) and reactance to (MD = 0.14; 95% CI = 0.05, 0.23, P = 0.003, ηp2  = 0.11) highly severe warnings but findings were inconclusive as to whether there was a difference in visual attention (MD = -0.55; 95% CI = -1.5, 0.41, P = 0.24, ηp2  = 0.02).

CONCLUSIONS

Subjective and objective (eye-tracking) measures of avoidance of health warnings on cigarette packs produce different results, suggesting these measure different constructs. Visual avoidance of warnings indicates low-level disengagement with warnings, while self-reported predicted avoidance reflects higher-level engagement with warnings.

Effects of Different Graphic Health Warning Types on the Intention to Quit Smoking

Anti-smoking advertisements are widely used to demonstrate to smokers the harm of smoking, and graphic health warnings (GHWs) are expected to have a positive effect on the intention to quit smoking. This study investigated which type of GHW (health-related threat (H-GHW) vs. social threat (S-GHW)) is more effective. Two types of GHWs for tobacco were shown to 28 daily smokers and 25 non-smokers while measuring their eye movements using an eye tracker. The time spent fixating on the GHWs was measured as an index of attentional bias. Participants were also asked to evaluate the unpleasantness of the images. They stated their intention to quit smoking in response to each image in a separate session. Multiple regression analysis was used to identify the effects of psychosocial factors on the intention to quit smoking in smokers and the intention to remain as non-smokers in the non-smokers. Both smokers and non-smokers reported greater unpleasantness and cessation intentions in response to H-GHWs than to S-GHWs. Non-smokers found both types of GHWs more unpleasant than smokers did. No differences were found in gaze fixation on GHWs between the two groups. When smokers viewed S-GHWs, the intention to quit smoking was greater as they felt more unpleasant. For non-smokers, the intention to remain non-smokers was greater when they felt more unpleasant and when the attention to H-GHWs was lower. Different psychological factors in anti-smoking advertisements are involved in the intention to quit smoking in smokers and to maintain a non-smoking status in non-smokers. Different approaches should be used according to the types of warning (e.g., warnings emphasizing a negative influence on others or on their own health) in anti-smoking campaigns.

Biomarkers and neuromodulation techniques in substance use disorders

Addictive disorders are a severe health concern. Conventional therapies have just moderate success and the probability of relapse after treatment remains high. Brain stimulation techniques, such as transcranial Direct Current Stimulation (tDCS) and Deep Brain Stimulation (DBS), have been shown to be effective in reducing subjectively rated substance craving. However, there are few objective and measurable parameters that reflect neural mechanisms of addictive disorders and relapse. Key electrophysiological features that characterize substance related changes in neural processing are Event-Related Potentials (ERP). These high temporal resolution measurements of brain activity are able to identify neurocognitive correlates of addictive behaviours. Moreover, ERP have shown utility as biomarkers to predict treatment outcome and relapse probability. A future direction for the treatment of addiction might include neural interfaces able to detect addiction-related neurophysiological parameters and deploy neuromodulation adapted to the identified pathological features in a closed-loop fashion. Such systems may go beyond electrical recording and stimulation to employ sensing and neuromodulation in the pharmacological domain as well as advanced signal analysis and machine learning algorithms. In this review, we describe the state-of-the-art in the treatment of addictive disorders with electrical brain stimulation and its effect on addiction-related neurophysiological markers. We discuss advanced signal processing approaches and multi-modal neural interfaces as building blocks in future bioelectronics systems for treatment of addictive disorders.

Brain Responses to Anti-Smoking Health Warnings In Youth

Purpose of the Review

Adolescents and young adults are a critical target for smoking prevention efforts. Health education is a key approach to these efforts, yet little is known about how adolescents and young adults process health information. One novel approach to understanding the neurobiological mechanisms of cognitive processing of public health communications is to use neuroimaging techniques to map the brain regions involved and make inferences about the neural systems engaged in the processing of health information. We reviewed recent studies that employed functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) to examine the brain responses of adolescents and young adults to anti-smoking health messages and videos.

Findings

This narrative literature review found that the medial prefrontal cortex, amygdala, and hippocampus were the brain regions most commonly engaged in response to health warnings. Developmental factors modulate the relationship between brain regions, regulated emotional reaction, and frontal regions that are responsible for decision making.

Summary

Research that integrates neurophysiology and behavior to study adolescent and young adult neurocognitive responses to health messaging is an important tool for identifying optimal methods to communicate the health hazards of smoking to this vulnerable population.

Single-response appetitive Pavlovian to instrumental transfer is suppressed by aversive counter-conditioning

Environmental stimuli, when paired with reward, can influence behaviour in maladaptive ways, for example, by encouraging overeating or addiction. Such behaviour can be sensitive to reward value manipulations, under circumscribed conditions, but whether reward-seeking is also sensitive to stimulus value manipulations remains unclear. Thus, the current experiment investigated whether reducing the hedonic value of a reward-paired stimulus would reduce reward-seeking behaviour. In total, 36 participants successfully completed a single-response Pavlovian-instrumental transfer (PIT) task with a counter-conditioning procedure. The Pavlovian phase associated three conditioned stimuli (CSs) with money at 100%, 50%, or 0% contingency. Counter-conditioning then followed for the experimental group, who saw the 100% CS paired with unpleasant pictures, while the control group saw only neutral images. Instrumental training required participants to learn a button-pressing response to win money. The transfer phase contrasted instrumental responding during baseline and CS presentation. Both experimental and control groups liked the 100% CS more than the other CSs after Pavlovian training, but counter-conditioning reduced this 100% CS liking. In transfer, the experimental group showed an abolition of appetitive PIT, while the control group showed maintenance of appetitive PIT. However, this group difference was only evident in response vigour, not response initiation. In summary, CS hedonic value influences cue-potentiated instrumental responding. More specifically, hedonic value of a reward-paired cue influences the vigour of instrumental responses, but not the decision to initiate a response. These data may have relevance to smoking cessation policies, where the introduction of health warnings may be viewed as a real-world example of counter conditioning.

Advancing Tobacco Product Warning Labels Research Methods and Theory: A Summary of a Grantee Meeting Held by the US National Cancer Institute

BACKGROUND

The World Health Organization's Framework Convention on Tobacco Control recommends prominent pictorial health warnings on tobacco products. To advance research methods, theory and understanding of how tobacco product warning labels (TPWLs) work, the US National Cancer Institute convened a grantee meeting. Our article describes the key insights that emerged from the meeting, situated within the context of the scientific literature.

RESULTS & RECOMMENDATIONS

First, presentations confirmed that large, pictorial TPWLs motivate people to try to quit and encourage smoking cessation. Second, pictorial TPWLs increase attention, knowledge, negative affect, and thinking about the warning. Third, TPWL studies have primarily used brief-exposure laboratory studies and observational studies of sustained exposure through national policy implementation, with a few randomized trials involving several weeks of exposure-with generally consistent results found across study designs. Fourth, novel assessment methods include brain imaging, eye tracking and "best-worst" discrete choice experiments. To make TPWL even more effective, research is needed to confirm the mechanisms of their influence, their impact across vulnerable populations, and their effect on social media posts about tobacco products. Research is also needed on the effect of trial design choices, the predictive validity of new measurement approaches, and warning labels for non-cigarette tobacco products.

IMPLICATIONS

To improve scientific understanding of TPWL effects, this grantee meeting summary describes emerging research methods, theory and study results. Directions for future research include examination of the mechanisms of how warning labels work across diverse tobacco products and across different populations and contexts.

Using Neuroscience to Inform Tobacco Control Policy

INTRODUCTION

Techniques employed in the field of neuroscience, such as eye tracking, electroencephalography, and functional magnetic resonance imaging, have been important in informing our understanding of the cognitive mechanisms underlying tobacco smoking. These techniques are now increasingly being used to investigate the likely impact of tobacco control policies.

AIMS AND METHODS

In this narrative review, we outline the value of these methodological approaches in answering policy-relevant tobacco control research questions, with a particular focus on their use in examining the impact of standardized cigarette packaging and health warnings. We also examine the limitations of these methodologies and provide examples of how they can be used to answer other policy-relevant questions.

RESULTS

We argue that neuroscience techniques can provide more objective evidence of the impacts of policy measures, allow investigation where it is not possible to conduct behavioral manipulations, and facilitate a deeper understanding of the cognitive mechanisms underlying the impacts of tobacco control policies such as standardized packaging, health warnings, point-of-sale displays, and mass media campaigns.

CONCLUSIONS

Rather than replacing more traditional methods of examining tobacco control measures, such as observational experiments, surveys, and questionnaires, neuroscience techniques can complement and extend these methods.

IMPLICATIONS

Neuroscience techniques facilitate objective examination of the mechanisms underlying the impacts of tobacco control measures. These techniques can therefore complement and extend other methodologies typically used in this field, such as observational experiments, surveys, and questionnaires.

Health Warning Labels for Smokeless Tobacco: The Impact of Graphic Images on Attention, Recall, and Craving

Introduction

Little research has examined the impacts of graphic health warnings on the users of smokeless tobacco products.

Methods

A convenience sample of past-month, male smokeless tobacco users (n = 142; 100% male) was randomly assigned to view a smokeless tobacco advertisement with a graphic health warning (GHW) or a text-only warning. Eye-tracking equipment measured viewing time, or dwell time, in milliseconds. Following the advertisement exposure, participants self-reported smokeless tobacco craving and recalled any content in the health warning message (unaided recall). Linear and logistic regression analyses evaluated the proportion of time viewing the GHW, craving, and GHW recall.

Results

Participants who viewed a GHW spent a significantly greater proportion of their ad viewing time on GHWs (2.87 seconds or 30%), compared to those viewing a text-only warning (2.05 seconds or 24%). Although there were no significant differences by condition in total advertisement viewing duration, those participants viewing a GHW had increased recall of health warning messages compared to the text-only warning (76% had any warning message recall compared to 53%; p < .05). Self-reported craving after advertisement exposure was lower in the GHW compared to text-only condition, but the difference was not statistically significant (a rating of 4.4 vs. 5.3 on a 10-point scale; p = .08).

Conclusions

GHWs attracted greater attention and greater recall of health warning messages compared to text-only warnings among rural male smokeless tobacco users.

Implications

Among a sample of rural smokeless tobacco users, GHWs attracted more attention and recall of health warning messages compared to text-only warnings when viewed within smokeless tobacco advertising. These findings provide additional empirical support that GHWs are an effective tobacco control tool for all tobacco products and advertisements.

Neural mechanisms underlying visual attention to health warnings on branded and plain cigarette packs

AIMS

To (1) test if activation in brain regions related to reward (nucleus accumbens) and emotion (amygdala) differ when branded and plain packs of cigarettes are viewed, (2) test whether these activation patterns differ by smoking status and (3) examine whether activation patterns differ as a function of visual attention to health warning labels on cigarette packs.

DESIGN

Cross-sectional observational study combining functional magnetic resonance imaging (fMRI) with eye-tracking. Non-smokers, weekly smokers and daily smokers performed a memory task on branded and plain cigarette packs with pictorial health warnings presented in an event-related design.

SETTING

Clinical Research and Imaging Centre, University of Bristol, UK.

PARTICIPANTS

Non-smokers, weekly smokers and daily smokers (n = 72) were tested. After exclusions, data from 19 non-smokers, 19 weekly smokers and 20 daily smokers were analysed.

MEASUREMENTS

Brain activity was assessed in whole brain analyses and in pre-specified masked analyses in the amygdala and nucleus accumbens. On-line eye-tracking during scanning recorded visual attention to health warnings.

FINDINGS

There was no evidence for a main effect of pack type or smoking status in either the nucleus accumbens or amygdala, and this was unchanged when taking account of visual attention to health warnings. However, there was evidence for an interaction, such that we observed increased activation in the right amygdala when viewing branded as compared with plain packs among weekly smokers (P = 0.003). When taking into account visual attention to health warnings, we observed higher levels of activation in the visual cortex in response to plain packaging compared with branded packaging of cigarettes (P = 0.020).

CONCLUSIONS

Based on functional magnetic resonance imaging and eye-tracking data, health warnings appear to be more salient on 'plain' cigarette packs than branded packs.