Brain default-mode network dysfunction in addiction

Focused Ultrasound Neuromodulation: Exploring a Novel Treatment for Severe Opioid Use Disorder

BACKGROUND

Opioid use disorder remains a critical health care challenge because current therapeutic strategies have limitations that result in high recurrence and deaths. We evaluated the safety and feasibility of focused ultrasound (FUS) neuromodulation to reduce substance cravings and use in severe opioid and co-occurring substance use disorders.

METHODS

This prospective, open-label, single-arm study enrolled 8 participants with severe, primary opioid use disorder with co-occurring substance use. Participants received a 20-minute session of low-intensity FUS (220 kHz) neuromodulation targeting the bilateral nucleus accumbens (NAc) with follow-up for 90 days. Outcome measures included safety, tolerability, feasibility, and effects of FUS neuromodulation by assessment of adverse events, substance craving, substance use (self-report, urine toxicology), mood, neurological examinations, and anatomical and functional magnetic resonance imaging (fMRI) at 1, 7, 30, 60, and 90 days post-FUS.

RESULTS

No serious device-related adverse events or imaging abnormalities were observed. Following FUS, participants demonstrated immediate (p < .002) and sustained (p < .0001; mean 91%) reductions in cue-induced opioid craving, with median ratings on a scale from 0 to 10 as follows: 6.9 (pre-FUS) versus 0.6 (90-day post-FUS). Craving reductions were similar for other illicit substances (e.g., methamphetamine [p < .002], cocaine [p < .02]). Decreases in opioid and co-occurring substance use were confirmed by urine toxicology. Seven participants remained abstinent at 30 days; 5 participants remained abstinent throughout 90 days post-FUS. Resting-state fMRI demonstrated decreased connectivity from the NAc to reward and cognitive regions post-FUS.

CONCLUSIONS

NAc FUS neuromodulation is safe and a potential adjunctive treatment for reducing drug cravings and use in individuals with severe opioid and co-occurring substance use disorders. Larger, sham-controlled, randomized studies are warranted.

Efficacy and safety of psilocybin for the treatment of substance use disorders: A systematic review

Psilocybin, a serotonergic psychedelic, may have therapeutic benefits for Substance Use Disorders (SUDs), but its overall efficacy and safety remain uncertain. This systematic review assessed the safety and efficacy of psilocybin for SUDs through a systematic database search conducted via OVID on May 22, 2024, and summarized 26 ongoing clinical trials registered on clinicaltrials.gov. Among 16 published included studies, 7 (43.75 %) focused on Alcohol Use Disorder (AUD), 5 (31.25 %) on Tobacco Use Disorder (TUD), and the remainder on Cocaine Use Disorder (CUD) (1, 6.25 %), Opioid Use Disorder (1, 6.25 %), Nicotine Use Disorder (1, 6.25 %), and multiple SUDs (1, 6.25 %). Study designs included open-label trials (5, 31.25 %), cross-sectional observational studies (6, 37.5 %), qualitative analyses (2, 12.5 %), one double-blind RCT (6.25 %), one pilot fMRI study (6.25 %), and one long-term follow-up (6.25 %). Psilocybin-assisted psychotherapy (PAP) was used in 10 studies (62.5 %), with doses ranging from microdosing to 20-40 mg/70 kg. PAP was associated with significant reductions in alcohol consumption, smoking cessation, and related psychological improvements. AUD studies reported fewer heavy drinking days, increased abstinence rates, and neuroimaging data indicating normalization of brain activity. TUD studies demonstrated high smoking abstinence rates, with mystical experiences predicting long-term outcomes. Findings for other SUDs were mixed, though psilocybin showed potential in reducing opioid dependence and nicotine use. Preliminary evidence supports psilocybin's efficacy and safety for AUD and TUD, particularly with psychotherapy, but larger clinical trials are needed to confirm these findings.

Psychostimulant and opioid abuse: A perspective from Uruguay

The number of people suffering from substance use disorder (SUD) worldwide has increased 45 % compared to the last decade according to the latest United Nations World Drug Report. This staggering increase, partly due to the recent COVID-19 pandemic, further raises the social and economic burden for nations. Prevention and treatment, two of the main strategies employed to curb the increase in SUD, have shown limited success despite our increasing understanding of the underlying processes of SUD. This review will focus on two main drug categories, psychostimulants, especially cocaine, and opioids since these are two of the most prevalent illicit drugs abused by the general public in low, middle, and high-income countries. The use of active adulterants (e.g. caffeine and illegally manufactured fentanyl, IMF) commonly employed in the preparation of illicit drugs will also be covered considering recent data which has shown that these adulterants may increase the health risk of psychostimulant and opioid users. Especially the high risk of the combined use of cocaine and IMF is detailed. An additional section will address drug abuse in women during pregnancy, as it constitutes a major public health concern due to the negative consequences on newborns and infants. Data from Uruguay is presented and compared to illegal drug use in other countries of South and North America. The rapidly changing drug market, together with the current prevalence of SUD, establishes the urgent need for new strategies and innovative treatments to manage this issue.

Dysfunction and recovery of the cortical connectome gradient and its association with gene expression profiles in methamphetamine and heroin use disorders

BACKGROUND

The hierarchy and segregation of community-based brain networks can be characterized by functional connectome gradient (FCG). Whether the cortical FCG was disrupted and could even be reversed after prolonged abstinence in substance use disorders (SUDs) remained unclear. Less is known about the underlying genetic basis.

METHODS

We utilized three independent datasets (n = 247) to investigate cortical FCG dysfunction and recovery after prolonged abstinence in methamphetamine use disorder (MUD) (n = 131), and validated in heroin use disorder (HUD) (n = 36). Furthermore, magnetic resonance spectroscopy (MRS) was employed to test the relationship between the glutamate in the ventral tegmental area (VTA) and cortical FCG. Postmortem gene expression was utilized to assess the transcriptional profiles related to cortical FCG alterations. Support vector regression (SVR) model based on the baseline cortical FCG was built to predict craving changes after long-term abstinence.

RESULTS

MUD and HUD individuals exhibited similar cortical FCG dysfunction and recovery at global and network levels, mainly in dorsal and ventral attentions network (DAN and VAN), frontoparietal network (FPN) and default mode network (DMN). The glutamate levels in VTA were correlated with the gradient distance between FPN and limbic network (LIM). The transcriptional profiles explained variance of the altered gradient pattern, with the most related genes enriched in synaptic signaling. Baseline cortical FCG significantly predicted craving changes after long-term abstinence.

CONCLUSIONS

We provided novel insights into the understanding of SUD as treatable health conditions from cortical FCG changes, which could be considered as the potential biomarkers of craving changes after prolonged abstinence for SUDs.

The role of sex in the association between cannabis use disorder and resting-state functional connectivity

While Cannabis use disorder (CUD) is twice as prevalent in males, females transition more quickly from heavy use to CUD and experience more severe withdrawal. These clinically relevant sex differences contrast the lack of knowledge about the underlying brain mechanisms. This study investigated the relationship between CUD and resting-state functional brain connectivity (RSFC), assessing potential sex differences herein. RSFC of the Salience Network (SN), Basal Ganglia Network (BGN), Executive Control Network (ECN), and Default Mode Network (DMN) was compared between 152 individuals (76 males) with CUD and 114 matched controls (47 males). Within the CUD group, relationships between RSFC and heaviness of cannabis use, age of onset, and CUD symptom severity, along with their associations with sex, were investigated. CUD and control groups showed similar RSFC across all networks, regardless of sex. In the CUD group, heavier cannabis use correlated with higher RSFC across all networks and earlier age of onset was related to higher RSFC in the anterior SN, BGN, left ECN, and dorsal DMN. These associations were similar for males and females. CUD severity was related to higher RSFC in the anterior SN, which was moderated by sex, with a positive association seen only in males. In conclusion, CUD may not necessarily be associated with altered RSFC. Individual use characteristics such age of onset and severity of use may determine the potential impact of cannabis use on RSFC in a largely similar way in males and females.

Differences in fMRI-based connectivity during abstinence or interventions between heroin-dependent individuals and healthy controls

The substantial personal, societal, and economic impacts of opioid addiction drive research investigating how opioid addiction affects the brain, and whether therapies attenuate addiction-related metrics of brain function. Evaluating the connectivity between brain regions is a useful approach to characterise the effects of opioid addiction on the brain. This work is a systematic narrative review of studies investigating the effect of abstinence or interventions on connectivity in people who are dependent on heroin (HD) and healthy controls (HC). We found that HD typically showed weaker connectivity than HC between three functional networks: the Executive Control Network, Default Mode Network, and the Salience Network. Abstinence and Transcranial Magnetic Stimulation (TMS) both attenuated differences in connectivity between HD and HC, often by strengthening connectivity in HD. We observed that increased connectivity due to abstinence or TMS consistently related to decreased craving/risk of relapse. Using these findings, we present an "urge and action framework" relating therapeutic factors contributing to craving/relapse, connectivity results, and neurobiological models of HD. To inform future research, we critically assessed the impact of study design and analysis methods on study results. We conclude that the weaker between-network connectivity in HD and HC and its relationship to craving/relapse merits further exploration as a biomarker and target for therapeutic interventions.

Altered integrated and segregated states in cocaine use disorder

Introduction

Cocaine use disorder (CUD) is a chronic brain condition that severely impairs cognitive function and behavioral control. The neural mechanisms underlying CUD, particularly its impact on brain integration-segregation dynamics, remain unclear.

Methods

In this study, we integrate dynamic functional connectivity and graph theory to compare the brain state properties of healthy controls and CUD patients.

Results

We find that CUD influences both integrated and segregated states, leading to distinct alterations in connectivity patterns and network properties. CUD disrupts connectivity involving the default mode network, frontoparietal network, and subcortical structures. In addition, integrated states show distinct sensorimotor connectivity alterations, while segregated states exhibit significant alterations in frontoparietal-subcortical connectivity. Regional connectivity alterations among both states are significantly associated with MOR and H3 receptor distributions, with integrated states showing more receptor-connectivity couplings. Furthermore, CUD alters the positive-negative correlation balance, increases functional complexity at threshold 0, and reduces mean betweenness centrality and modularity in the critical subnetworks. Segregated states in CUD exhibit lower normalized clustering coefficients and functional complexity at a threshold of 0.3. We also identify network properties in integrated states that are reliably correlated with cocaine consumption patterns.

Discussion

Our findings reveal temporal effects of CUD on brain integration and segregation, providing novel insights into the dynamic neural mechanisms underlying cocaine addiction.

Unveiling causal relationships between tobacco use phenotypes and neuroimaging: Insights from bidirectional Mendelian randomization and bibliometric analysis

Smoking is considered the most common addictive behavior worldwid. However, it is not systematically investigated whether there are bidirectional causal associations between tobacco use and neuroimaging, which might provide potential neural biomarkers or therapeutic neuro-targets for tobacco abuse or rehabilitation. In this study, using Mendelian randomization (MR), we explored both forward and reverse causal relationships between 4 tobacco use phenotypes (including Cigarettes per day, Smoking initiation, Age of initiation and Smoking cessation) and 209 neuroimaging features involving brain function and structure. Besides, we conducted a bibliometric analysis to find corresponding global trends of knowledge and specialized research areas. After Bonferroni correction, positive causal associations between cerebral global functional connectivity (FC) and smoking cessation, as well as between age of initiation and default mode network (DMN) structural connectivity (SC) were revealed; there were negative causal associations between mean diffusivity of left medial lemniscus and cigarette per day. Up to now, we also reveal that functional neuroimaging especially FC dominated smoking research field. Therefore, the discovery of causal relationships between smoking-related phenotypes and multi-modal cerebral alterations will promote a comprehensive understanding of tobacco addiction from cerebral function and structure perspective, facilitating the progression of personal treatment and risk prediction.

Effects of gaming content from social media on individuals with internet gaming disorder: an fMRI study

Internet gaming disorder is an increasing public health problem due to the widespread availability of online gaming. Social media platforms drive this trend by enabling gameplay sharing and increasing user engagement, potentially reinforcing addictive gaming behaviors. Understanding how gaming content exposure on social media affects brain activity in individuals with internet gaming disorder is crucial. This study aimed to investigate gaming content neural responses on social media in individuals with internet gaming disorder using functional magnetic resonance imaging. We aimed to determine differences in activation patterns that contribute to understanding the neurobiological underpinnings of internet gaming disorder by examining brain activity in these individuals and comparing it to healthy controls. Additionally, we investigated the association of brain activity with clinical characteristics (internet gaming disorder severity and illness duration). The participants with internet gaming disorder demonstrated increased bilateral orbitofrontal cortex, bilateral hippocampus, left precuneus, and right superior temporal gyrus activation in response to gaming-related cues on social media compared to healthy controls. Additionally, internet gaming disorder severity and illness duration correlated with left hippocampus activation levels. These results improve our understanding of how gaming-related content on social media affects individuals with internet gaming disorder. Our findings provide valuable information into the neurobiological features of internet gaming disorder and help develop effective treatment interventions.

Regulation of craving and underlying resting-state neural circuitry predict hazard of smoking lapse

Among individuals with substance use disorders, clinical outcomes may be improved by identifying brain-behavior models that predict drug re/lapse vulnerabilities such as the ability to regulate drug cravings and inhibit drug use. In a sample of nicotine-dependent adult cigarette smokers (N = 213), this laboratory study examined associations between regulation of craving (ROC) efficacy and smoking lapse, utilized functional connectivity multivariate pattern analysis (FC-MVPA) and seed-based connectivity (SBC) analyses to identify resting-state neural circuitry underlying ROC efficacy, and then examined if the identified ROC-mediated circuitry predicted hazard of smoking lapse. Regarding behavior, worse ROC efficacy predicted a greater hazard of smoking lapse. Regarding brain and behavior, FC-MVPA identified 29 brain-wide functional clusters associated with ROC efficacy. Follow-up SBC analyses using 9 of the FC-MVPA-derived clusters identified a total of 64 resting-state edges (i.e., cluster-to-cluster connections) underlying ROC efficacy, 10 of which were also associated with the hazard of smoking lapse. ROC efficacy edges also associated with smoking lapse were largely composed of connections between frontal-striatal-limbic clusters and sensory-motor clusters and better behavioral outcomes were associated with stronger resting-state FC. Findings suggest that both ROC efficacy and underlying resting-state neural circuitry may inform prediction models of re/lapse vulnerabilities and serve as treatment targets for cessation interventions.

Differential large-scale network functional connectivity in cocaine-use disorder associates with drug-use outcomes

Cocaine-use disorder (CUD) affects both structure and function of the brain. A triple network model of large-scale brain networks has been useful for identifying aberrant resting-state functional connectivity (rsFC) associated with mental health disorders including addiction. The present study investigated differences between people with CUD vs. controls (CONs) and whether putative differences were associated with drug-use outcomes. Participants with CUD (n = 38) and CONs (n = 34) completed a resting functional magnetic resonance imaging (fMRI) scan. Participants with CUD completed several mental health measures and participated in an 8-week, drug-use outcomes phase. A classification framework based on the triple network model was built, and triple networks (salience [SN], executive control [ECN], default mode [DMN]) and subcortical (striatum [ST], hippocampus/amygdala) regions were identified with the algorithm of group-information-guided independent components analysis (GIG-ICA) and subsequent support-vector machines. This classifier achieved 77.1% accuracy, 73.8% sensitivity, and 80.0% specificity, with an area under the curve of 0.87 for distinguishing CUD vs. CON. The two groups differed in SN-anterior DMN (aDMN) and ECN-aDMN rsFC, with the CUD group exhibiting stronger rsFC compared to CONs. They also differed in rsFC between several subcortical and triple networks, with CUD generally showing a lack of rsFC. Within the CUD group, ST-aDMN and ST-rECN rsFC were associated with differential drug-use outcomes. Exploratory results suggested SN-aDMN rsFC was associated with anxiety symptoms. These results add to the growing literature showing aberrant triple network and subcortical rsFC associated with substance use disorders. They suggest the aDMN specifically may underlie important differences between people with CUD and CONs and may be a potential target for intervention.

Psychedelic Use and Behavioral Addictions

Recent clinical trials on classic psychedelics for depression and anxiety have raised questions about their potential to treat other psychiatric conditions. Evidence from pre-clinical and clinical research suggests psychedelics may help with substance use disorders, with ongoing registered trials. Behavioral addictions, sharing features with substance addictions, may also respond to psychedelic treatment. This study examined self-reported symptoms of problem gambling, sexual addiction, compulsive buying, and eating disorders in a community sample (N = 1107), alongside measures of well-being (self-transcendence, personal growth, depression/anxiety, etc.), and use of psychedelics and other psychoactive drugs. Significant positive correlations emerged among well-being measures and among behavioral addiction symptoms, with inverse correlations between well-being and behavioral addictions. Psychedelic users reported greater well-being and lower behavioral addiction symptoms, even after controlling for demographics and other drug use. Principal components analysis showed that behavioral addictions formed a single factor, which was combined into a composite score. Multiple regression analyses revealed that major stimulant, alcohol, and nicotine vaping use predicted higher behavioral addiction scores, while psychedelic use uniquely predicted lower scores. These findings suggest psychedelics may aid in treating behavioral addictions. A controlled pilot study or clinical trial is warranted to explore this therapeutic potential further.

Understanding Altered Dynamics in Cocaine Use Disorder Through State Transitions Mediated by Artificial Perturbations

Background/Objectives: Cocaine use disorder (CUD) poses a worldwide health challenge, with severe consequences for brain function. However, the phase dynamics underlying CUD and the transitions between CUD and health remain poorly understood. Methods: Here, we used resting-state functional magnetic resonance imaging (fMRI) data from 43 CUD patients and 45 healthy controls (HCT). We performed empirical analysis to identify phase-coherence states and compared their probabilities of occurrence between conditions. To further explore the underlying mechanism, we employed computational modeling to replicate the observed state probabilities for each condition. These generated whole-brain models enabled us to simulate external perturbations and identify optimal brain regions mediating transitions between HCT and CUD. Results: We found that CUD was associated with a reduced occurrence probability of the state dominated by the default mode network (DMN). Perturbing the nucleus accumbens, thalamus, and specific regions within the default mode, limbic and frontoparietal networks drives transitions from HCT to CUD, while perturbing the hippocampus and specific regions within the visual, dorsal attention, and DMN facilitates a return from CUD to HCT. Conclusions: This study revealed altered DMN-related dynamics in CUD from the phase perspective and provides potential regions critical for state transitions. The results contribute to understanding the pathogenesis of CUD and the development of therapeutic stimulation strategies.

The glutamatergic projections from the PVT to mPFC govern methamphetamine-induced conditional place preference behaviors in mice

BACKGROUND

Drug addiction is closely related to the dysregulation of complex neural circuits. However, the neural connections underlying the symptoms of methamphetamine (METH)-induced addiction have yet to be elucidated.

METHODS

We conducted ΔFosB (Delta FBJ murine osteosarcoma viral oncogene homolog B) associated immunofluorescence and electrophysiological recording experiments to measure the neural activity of paraventricular thalamus (PVT) neurons in METH treated mice. Then, the METH-mediated conditional place preference (CPP) behaviors were evaluated after chemogenetic manipulation of PVT neurons. Additionally, the neural projection from PVT to medial prefrontal cortex (mPFC) was verified through Adeno-associated virus (AAV) mediating neural tracing method, and its role on METH-mediated CPP behaviors was determined using chemogenetic and neural ablation strategies.

RESULTS

We found that glutamatergic neurons in PVT were activated by METH. Activating the glutamatergic neurons in PVT promoted the METH-mediated CPP behaviors, while inhibiting these neurons attenuated the CPP behaviors. Moreover, we observed PVT neurons showed robust neuronal projections to mPFC, activation of the mPFC→projecting neurons in PVT or the afferent terminals in mPFC derived from PVT enhanced METH-mediated CPP performance, and ablating the mPFC neurons receipting neural projection from PVT impeded these increased METH-mediated CPP phenotypes.

LIMITATIONS

The underlying molecular mechanism of the dysfunctional PVT neurons after METH treatment and the PVT neurons regulating the activity of mPFC target neurons remains unclear.

CONCLUSIONS

These results shed light on that PVT is a key METH addiction-controlling nucleus, and PVT → mPFC projection regulated METH-mediated CPP behaviors, which could serve as a vital pathway for morbidity and treatment for METH-mediated addiction.

Effects of insecure attachment on fMRI resting state functional connectivity in poly drug use disorder

BACKGROUND

Insecure adult attachment has previously been linked to more severe psychopathology and to alterations within neuronal connectivity on a structural as well as functional level. Little is known about the resting state functional connectivity (rs-FC) of the attachment system in patients suffering from poly-drug use disorder (PUD).

METHODS

The present study investigated rs-FC at two measuring points (t1: ROI-to-ROI; t2: seed-to-voxel) in a sample of PUD patients (n = 33; Age: M = 30y; SD = 8y; Female = 15%). Adult attachment was measured with the German version of the Experiences in Close Relationships Scale (ECR-RD8). Furthermore, insecure attachment was correlated with depressive symptoms (ADS), trait anxiety (STAI) and general psychopathology (BSI-53).

RESULTS

More insecure attachment was associated with increased trait anxiety, depressive and general psychiatric symptom burden in patients. Furthermore, we observed time-stable links between insecure adult attachment and increased rs-FC between the left lateral parietal default mode network (DMN LP) and bilateral parts of the salience network, as well as decreased rs-FC between DMN LP and medial parts of the DMN.

DISCUSSION

Implications of the present study are highlighting the association between attachment security and brain areas related to affect regulation.

Neuroscience-informed psychoeducation for addiction: a conceptual and feasibility study

Over the past few decades, our understanding of substance use disorders (SUD) has been reshaped by evidence from neuroscience, which suggests that SUD are characterized by specific neuromarkers that transcend traditional diagnostic boundaries and act as pre-diagnostic markers that could be targeted through preventive attempts. Connectivity-based neuromarkers or brain networks have emerged as a promising framework, providing new insights into the neurocognitive mechanisms of SUD. Utilizing this data-driven framework assists prevention and intervention developers in offering a non-judgmental insight for adolescents regarding the potential vulnerability of neurocognitive systems to continued substance use. Given the importance of such awareness, this paper proposes a neural network-informed approach based on research domain criteria (RDoC) to characterize the content of neuroscience-informed psychoeducation designed for SUD. Furthermore, we argue that various features related to content and structure need to be considered when developing such interventions delivered through digital platforms (e.g., apps and websites). Finally, we introduce a theory-driven app called "NIPA", developed with the aim of increasing adolescents' awareness and resilience to the effects of drugs and other emotional triggers on brain and cognitive functions.

Rest-Activity Rhythms, Their Modulators, and Brain-Clinical Correlates in Opioid Use Disorder

Importance

Sleep and circadian disruptions are highly prevalent in opioid use disorder (OUD) and are a barrier to successful treatment and recovery; yet few objective data are available, especially for individuals in OUD treatment with opioid agonist therapy. If disruptions remain present despite OUD treatment, this information would yield potential new targets for adjunctive therapy.

Objective

To systematically investigate different aspects of rest-activity rhythms (RAR), including sleep, physical activity, circadian rhythmicity, and brain functional correlates in individuals with OUD.

Design, Setting, and Participants

This cross-sectional study conducted from October 12, 2017, through January 11, 2024, recruited participants with OUD from treatment programs or the community in the District of Columbia, Maryland, and Virginia area. Participants included individuals with OUD treated with methadone or buprenorphine, individuals with OUD who remained abstinent without medications, and healthy controls (HCs). Healthy participants were recruited from advertisements. Statistical analyses were conducted between March 1 and May 31, 2024.

Main Outcomes and Measures

In total, 21 RAR features were derived from 1-week actigraphy data, and principal components were used to extract independent RAR components. Modulators and brain and clinical correlates of RAR were also examined.

Results

This study included 73 participants (46 [63%] male; mean [SD] age, 43.5 [11.3] years). Among 42 patients with OUD (16 [38%] female; mean [SD] age, 42.7 [11.4] years), 33 receiving medications for opioid use disorder (MOUD) exhibited greater sleep-wake irregularity than 9 patients without MOUD (mean difference, 0.85 [95% CI, 0.00-1.69]) or 31 age- and sex-matched HCs (11 [36%] female; mean [SD] age, 44.5 [11.3] years; mean difference, 0.75 [95% CI, 0.19-1.31). Among participants receiving MOUD, greater sleep irregularity was associated with longer heroin use history (r26 = 0.45; P = .02) and lower daytime light exposure (r33 = -0.57; P < .001). Compared with HCs, participants with OUD exhibited lower fractional occupancy (percentage of occurrence) in a default mode network-dominated brain state, with individuals experiencing more pronounced sleep-wake irregularities displaying exacerbated impairments (r23 = -0.55; P = .007).

Conclusions and Relevance

Findings of this cross-sectional study showed that sleep irregularity in participants with OUD receiving opioid agonist medications correlated with years of opioid misuse and shorter daylight exposures and was associated with impaired brain state dynamics. These findings suggest that interventions increasing light exposure may improve sleep-wake irregularity and brain functional network dynamics in individuals with OUD receiving opioid agonist medications.

Neural cue reactivity and intrinsic functional connectivity in individuals with alcohol use disorder following treatment with topiramate or naltrexone

RATIONALE

Both topiramate and naltrexone have been shown to affect neural alcohol cue reactivity in alcohol use disorder (AUD). However, their comparative effects on alcohol cue reactivity are unknown. Moreover, while naltrexone has been found to normalize hyperactive localized network connectivity implicated in AUD, no studies have examined the effect of topiramate on intrinsic functional connectivity or compared functional connectivity between these two widely used medications.

OBJECTIVE

This study compared topiramate versus naltrexone on alcohol cue-elicited brain activation and intrinsic functional connectivity in patients with alcohol use disorder.

METHODS

Forty-seven participants with alcohol use disorder received daily topiramate (titrating the dose up to 200 mg/day n = 21) or naltrexone (50 mg/day, n = 26) for at least 6 weeks. Using functional magnetic resonance imaging (fMRI), we examined intrinsic functional connectivity during rest and alcohol cue-elicited neural activation during a visual alcohol cue reactivity task 120 min following treatment administration. Functional connectivity and alcohol cue reactivity and percentage of heavy drinking days (% HDD) associations were assessed.

RESULTS

No differences in either intrinsic functional connectivity or alcohol cue-elicited neural activity were seen between topiramate and naltrexone-treated groups. Overall, participants showed increased alcohol cue-elicited activation in three clusters spanning occipital regions involved in visual recognition of stimuli, and hypoactivation to both alcohol and control cues in three clusters involved in salience attribution and processing of emotional valence of external stimuli. No differences between topiramate versus naltrexone were observed for either functional measure or associations with post-scan % HDD.

CONCLUSIONS

Topiramate and naltrexone enacted comparable alcohol cue reactivity and intrinsic functional connectivity patterns. Some overall responses of increased brain activation to alcohol cues in visual processing regions coupled with reduced activation to alcohol and control cues were evidenced for both treatments. These activation patterns were in regions expected to show attenuation of brain activity resulting from treatment. Topiramate and naltrexone may thus enact functional effects through similar modulation of functional neural activity in individuals with AUD.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03479086 https://www.

CLINICALTRIALS

gov/study/NCT03479086 .

Brain structural differences in cocaine use disorder: Insights from multivariate and neurotransmitter analyses

Cocaine use disorder (CUD) is a chronic and relapsing neuropsychiatric disorder characterized by structural and functional brain lesions, posing a significant public health challenge. While the disruptive effects of cocaine on neurotransmitter systems (receptors/transporters) have been well established, the patterns of brain structural abnormalities in CUD and its interaction with other factors remain an ongoing topic of investigation. We employed source-based morphometry (SBM), a multivariate approach on 50 CUD participants and 50 matched healthy controls from the public SUDMEX CONN dataset. This method allowed us to identify co-varying patterns of brain tissue volume differences, and further explore the effect of average cocaine dosage through moderation analysis. Spatial correlation analysis was also performed to examine micro-macro structural consistency between tissue volume variations and chemoarchitectural distribution of dopamine and serotonin. Our SBM analysis findings were consistent with reward-related neuroadaptations in the striato-thalamo-cortical and limbic pathways and also exhibited co-localization with the distribution of dopamine and serotonin systems. The moderation analysis suggested that the average dosage positively strengthens cocaine consumption years' effect on brain structures. By integrating our findings of gray and white matter volume differences and corresponding neurotransmitter profiles, this comprehensive view not only strengthens our understanding of the brain's structural abnormalities in CUD, but also reveals potential mechanisms underlying its development and progression.

Targeting VMPFC-amygdala circuit with TMS in substance use disorder: A mechanistic framework

The ventromedial prefrontal cortex (VMPFC), located along the medial aspect of the frontal area, plays a critical role in regulating arousal/emotions. Its intricate connections with subcortical structures, including the striatum and amygdala, highlight the VMPFC's importance in the neurocircuitry of addiction. Due to these features, the VMPFC is considered a promising target for transcranial magnetic stimulation (TMS) in substance use disorders (SUD). By the end of 2023, all 21 studies targeting VMPFC for SUD used anatomical landmarks (e.g., Fp1/Fp2 in the EEG system) to define coil location with a fixed orientation. Nevertheless, one-size-fits-all TMS over VMPFC has yielded variable outcomes. Here, we suggested a pipeline based on a tailored TMS targeting framework aimed at optimally modulating the VMPFC-amygdala circuit on an individual basis. We collected MRI data from 60 participants with methamphetamine use disorders (MUDs). We examined the variability in TMS target location based on task-based functional connectivity between VMPFC and amygdala using psychophysiological interaction (PPI) analysis. Electric fields (EF) were calculated for fixed vs. optimized location (Fp1/Fp2 vs. individualized maximal PPI), orientation (AF7/AF8 vs. optimized algorithm) and intensity (constant vs. adjusted) to maximize target engagement. In our pipeline, the left medial amygdala, identified as the brain region with the highest (0.31 ± 0.29) fMRI drug cue reactivity, was selected as the subcortical seed region. The voxel with the most positive amygdala-VMPFC PPI connectivity in each participant was considered the individualized TMS target (MNI-coordinates: [12.6, 64.23, -0.8] ± [13.64, 3.50, 11.01]). This individualized VMPFC-amygdala connectivity significantly correlated with VAS craving after cue exposure (R = 0.27, p = 0.03). Coil orientation was optimized to increase EF strength over the targeted circuit (0.99 ± 0.21 V/m vs. the fixed approach: Fp1: 0.56 ± 0.22 and Fp2: 0.78 ± 0.25 V/m) and TMS intensity was harmonized across the population. This study highlights the potential of an individualized VMPFC targeting framework to enhance treatment outcomes for addiction, specifically modulating the personalized VMPFC-amygdala circuit.

Exploring Problematic TikTok Use and Mental Health Issues: A Systematic Review of Empirical Studies

BACKGROUND

Since its launch in 2017, TikTok has rapidly emerged as a major player in the digital landscape, amassing over a billion active users. Its engaging features have raised concerns about potential problematic use and negative mental health outcomes. Despite increasing scholarly attention, a consolidated understanding of TikTok's problematic use potential and implications remains elusive This systematic review synthesizes empirical research on problematic TikTok use and its impact on mental health.

METHODS

This review followed PRISMA Statement 2020 guidelines and conducted a comprehensive search across PubMed, Embase, Scopus, Web of Science, and PsycINFO databases until July 10, 2024. Keywords included terms related to TikTok use, addiction, and problematic use. Studies were included based on empirical focus and publication in peer-reviewed journals. Data extraction comprised study characteristics, measures of TikTok problematic use, and related mental health outcomes. Quality assessment used JBI, Cochrane's RoB 2, MMAT, CASP, and NOS tools. The protocol was registered in OSF: https://osf.io/cjf97.

RESULTS

This review included 26 studies, involving a total of 11 462 participants. The pooled prevalence of TikTok use was estimated at 80.19%, with the highest rates observed among people aged 18 to 29 years, where it reached 85.4%. Frequent use of TikTok was closely linked with an increase in symptoms of anxiety and depression, especially in users aged under 24 years. Female users were more likely to experience problematic TikTok use, with 67.3% of such cases found among female university students. Moreover, higher addiction scores were noted among individuals from lower socioeconomic backgrounds and those who had higher levels of neuroticism.

CONCLUSION

The findings of this review highlight the growing concern surrounding the impact of problematic TikTok use on mental health, particularly among younger and more vulnerable populations. It is imperative for stakeholders to prioritize the integration of digital literacy and media literacy into educational curricula. Moreover, the involvement of caregivers through guided mediation and the establishment of clear usage parameters could play a crucial role in managing screen time, particularly for younger users. To improve the current landscape of empirical research, longitudinal and interventional research is warranted.

Sleep Deprivation Effects on Brain State Dynamics Are Associated With Dopamine D2 Receptor Availability Via Network Control Theory

BACKGROUND

Sleep deprivation (SD) negatively affects brain function. Most brain imaging studies have investigated the effects of SD on static brain function. SD effects on functional brain dynamics and their relationship with molecular changes remain relatively unexplored.

METHODS

We used functional magnetic resonance imaging to examine resting-brain state dynamics after one night of SD compared with rested wakefulness (N = 41) and assessed the association of brain state dynamics with striatal brain dopamine D2 receptor availability measured by positron emission tomography [11C]raclopride using network control theory.

RESULTS

SD reduced dwell time and persistence probabilities, with the strongest effects in two brain states, one characterized by high default mode network and low dorsal attention network activity and the other by high frontoparietal network and low somatomotor network activity. Using network control theory, we showed that after SD, there was an overall increase in the control energy required for brain state transitions, with effects varying for different brain state transitions. Control energy requirement was negatively associated with transition probabilities under SD and restful wakefulness and accounted for SD-induced changes in transition probabilities. Alteration in the energy landscape was associated with SD-induced changes in striatal D2 receptor distribution.

CONCLUSIONS

These findings demonstrate altered occurrence of internally and externally oriented brain states following acute SD and suggest an association with energy requirements for brain state transitions modulated by striatal D2 receptors.

The Limbic System in Co-Occurring Substance Use and Anxiety Disorders: A Narrative Review Using the RDoC Framework

Substance use disorders (SUDs) and anxiety disorders (ADs) are highly comorbid, a co-occurrence linked to worse clinical outcomes than either condition alone. While the neurobiological mechanisms involved in SUDs and anxiety disorders are intensively studied separately, the mechanisms underlying their comorbidity remain an emerging area of interest. This narrative review explores the neurobiological processes underlying this comorbidity, using the Research Domain Criteria (RDoC) framework to map disruptions in positive valence, negative valence, and cognitive systems across the three stages of the addiction cycle: binge/intoxication, withdrawal/negative affect, and preoccupation/anticipation. Anxiety and substance use play a reciprocal role at each stage of addiction, marked by significant psychosocial impairment and dysregulation in the brain. A more thorough understanding of the neural underpinnings involved in comorbid SUDs and anxiety disorders will contribute to more tailored and effective therapeutic interventions and assessments.

Similarities and differences in dynamic properties of brain networks between internet gaming disorder and tobacco use disorder

BACKGROUND

Internet gaming disorder (IGD) and tobacco use disorder (TUD) are two major addiction disorders that result in substantial financial loss. Identifying the similarities and differences between these two disorders is important to understand substance addiction and behavioral addiction. The current study was designed to compare these two disorders utilizing dynamic analysis.

METHOD

Resting-state data were collected from 35 individuals with IGD, 35 individuals with TUD and 35 healthy controls (HCs). Dynamic coactivation pattern analysis was employed to decipher their dynamic patterns.

RESULTS

IGD participants showed decreased coactivation patterns within the default mode network (DMN) and between the DMN and the salience network (SN). The SN showed reduced coactivation patterns with the executive control network (ECN) and DMN, and the ECN showed decreased coactivation patterns with the DMN. In the TUD group, the DMN exhibited decreased coactivation patterns with the SN, the SN exhibited reduced coactivation patterns with the DMN and ECN, and the ECN showed decreased coactivation patterns with the DMN and within the ECN. Furthermore, the triple network model was fitted to the dynamic properties of the two addiction disorders. Decoding analysis results indicated that addiction-related memory and memory retrieval displayed similar dysfunctions in both addictions.

CONCLUSION

The dynamic characteristics of IGD and TUD suggest that there are similarities in the dynamic features between the SN and DMN and differences in the dynamic features between the DMN and ECN. Our results revealed that the two addiction disorders have dissociable brain mechanisms, indicating that future studies should consider these two addiction disorders as having two separate mechanisms to achieve precise treatment for their individualized targets.

Synergistic, multi-level understanding of psychedelics: three systematic reviews and meta-analyses of their pharmacology, neuroimaging and phenomenology

Serotonergic psychedelics induce altered states of consciousness and have shown potential for treating a variety of neuropsychiatric disorders, including depression and addiction. Yet their modes of action are not fully understood. Here, we provide a novel, synergistic understanding of psychedelics arising from systematic reviews and meta-analyses of three hierarchical levels of analysis: (1) subjective experience (phenomenology), (2) neuroimaging and (3) molecular pharmacology. Phenomenologically, medium and high doses of LSD yield significantly higher ratings of visionary restructuralisation than psilocybin on the 5-dimensional Altered States of Consciousness Scale. Our neuroimaging results reveal that, in general, psychedelics significantly strengthen between-network functional connectivity (FC) while significantly diminishing within-network FC. Pharmacologically, LSD induces significantly more inositol phosphate formation at the 5-HT2A receptor than DMT and psilocin, yet there are no significant between-drug differences in the selectivity of psychedelics for the 5-HT2A, 5-HT2C, or D2 receptors, relative to the 5-HT1A receptor. Our meta-analyses link DMT, LSD, and psilocybin to specific neural fingerprints at each level of analysis. The results show a highly non-linear relationship between these fingerprints. Overall, our analysis highlighted the high heterogeneity and risk of bias in the literature. This suggests an urgent need for standardising experimental procedures and analysis techniques, as well as for more research on the emergence between different levels of psychedelic effects.

Clinical Effects of Psychedelic Substances Reported to United States Poison Centers: 2012 to 2022

STUDY OBJECTIVE

Psychedelic substances use is increasing in the United States (US). The approval of new psychedelic drugs and legalization of natural psychedelic substances will likely further increase exposures and subsequent adverse events. The study objective is to describe the clinical effects, therapies, and medical outcomes of patients with psychedelic exposures reported to US poison centers.

METHODS

We performed a retrospective, cross-sectional study on psychedelic exposures reported to the National Poison Data System from January 1, 2012, to December 31, 2022. We categorized exposures into groups: hallucinogenic amphetamines, lysergic acid diethylamide, tryptamines (such as N, N-dimethyltryptamine), phencyclidine, hallucinogenic mushrooms, hallucinogenic plants, and ketamine and ketamine analogs. We summarized effects, treatments, and outcomes and evaluated associations with logistic regression and odds ratios.

RESULTS

Our sample included 54,605 cases. There were concomitant exposures in 41.1% (n=22,460) of cases. Hallucinogenic mushroom exposures increased most over the study period from 593 in 2012 to 1,440 in 2022. Overall, 27,444 (50.3%) psychedelic exposures had symptoms that required treatment, severe residual or prolonged symptoms, or death. Cardiovascular effects were common, especially with hallucinogenic amphetamine exposures (31.1%). Patients managed in or referred to a health care facility received medical therapies in 62.4% of cases, including sedation (32.9%) and respiratory interventions (10.3%).

CONCLUSION

Over half of psychedelic exposures reported to US poison centers had symptoms that required treatment, severe residual or prolonged symptoms, or death. Increases in psychedelic use may lead to increased frequency of adverse events and health care utilization.

Catecholaminergic Modulation of Large-Scale Network Dynamics Is Tied to the Reconfiguration of Corticostriatal Connectivity

Large-scale brain network function is critical for healthy cognition, yet links between such network function, neurochemistry, and smaller-scale neurocircuitry are unclear. Here, we evaluated 59 healthy individuals using resting-state fMRI to determine how network-level temporal dynamics were impacted by two well-characterized pharmacotherapies targeting catecholamines: methylphenidate (20 mg) and haloperidol (2 mg)-administered via randomized, double-blind, placebo-controlled design. Network temporal dynamic changes were tested for links with drug-induced alterations in complex corticostriatal connections as this circuit is a primary site of action for both drugs. Methylphenidate increased time in the default mode network state (DMN p < 0.001) and dorsal attention network state (DAN p < 0.001) and reduced time in the frontoparietal network state (p < 0.01). Haloperidol increased time in a sensory motor-DMN state (p < 0.01). The magnitude of change in network dynamics induced by methylphenidate vs. placebo correlated with the magnitude of methylphenidate-induced rearrangement of complex corticostriatal connectivity (R = 0.32, p = 0.014). Haloperidol did not alter complex corticostriatal connectivity. Methylphenidate enhanced time in network states involved in internal and external attention (DMN and DAN, respectively), aligning with methylphenidate's established role in attention. Methylphenidate also significantly changed complex corticostriatal connectivity by altering the relative strength between multiple corticostriatal connections, indicating that methylphenidate may shift which corticostriatal connections are prioritized relative to others. Findings show that these corticostriatal circuit changes are linked with large-scale network temporal dynamics. Collectively, these findings provide a deeper understanding of large-scale network function, set a stage for mechanistic understanding of network engagement, and provide useful information to guide medication use based on network-level effects. Trial Registration: Registry name: ClinicalTrials.gov; URL: Brain Networks and Addiction Susceptibility-Full Text View-ClinicalTrials.gov; URL Plain text: https://classic.clinicaltrials.gov/ct2/show/NCT01924468; Identifier: NCT01924468.

Resting-state EEG microstate analysis of internet gaming disorder and alcohol use disorder

INTRODUCTION

To investigate the neurophysiological aspects of addiction, the microstate characteristics of internet gaming disorder (IGD), alcohol use disorder (AUD), and healthy control (HC) groups were compared using resting-state electroencephalography (EEG).

METHODS

In total, 199 young adults (75 patients with IGD, 57 patients with AUD, and 67 HCs) participated in this study. We conducted EEG microstate analysis among the groups and also compared the obtained parameters with the results of psychological assessments.

RESULTS

The global explained variance, occurrence, and coverage of microstate C were significantly lower in the AUD group than in the IGD group. Additionally, rates of transition from microstates A, B, and D to C were significantly lower in the AUD group than in the IGD group, whereas rates of transition from microstate A to B were lower in the IGD group compared to HCs. Furthermore, the occurrence of microstate C and transition from microstate B to C were negatively correlated with the Alcohol Use Disorder Identification and Behavioural Inhibition Scale score.

CONCLUSION

There were significant differences in microstate characteristics among the groups, which correlated with the psychological scores. These findings suggest that microstate features can be used as neuromarkers in clinical settings to differentiate between addictive disorders and evaluate the pathophysiology of AUD and IGD.

Interoceptive Processing in Substance Use Disorders (SUDs): From the Neuroanatomy to Insights from Computational Models and Predictive Coding Frameworks

Substance use disorders (SUDs) represent complex public health challenges characterized by a blend of genetic, cognitive, environmental, and psychosocial factors. This chapter explores the critical role of interoceptive processing - the internal sensing of physiological states - in the neurobiology and treatment of SUDs. Interoceptive dysfunctions are highlighted as central to the craving, emotional regulation, and decision-making processes that underpin addictive behaviors. The importance of the insula in sustaining drug use, particularly nicotine, underscores a broader involvement of interoceptive pathways in SUDs. Altered interoceptive processing is evident across various SUDs, where individuals demonstrate both a heightened sensitivity to drug-related cues and a diminished ability to process aversive stimuli, suggesting substantial neurobiological underpinnings that complicate treatment outcomes. Moreover, we delve into the theoretical and computational approach to understanding interoceptive processing in SUDs. This perspective utilizes a predictive coding framework, positing that the brain continuously generates and updates predictions about internal states based on sensory inputs. In SUDs, disruptions in this predictive mechanism can lead to inaccuracies in interoceptive perception, contributing significantly to the compulsive nature of drug-seeking behaviors and the challenges associated with treatment. We explore how computational models, such as Bayesian inference, provide insights into the interplay between expected and received interoceptive signals, highlighting the role of hyper-precise prior beliefs in the persistence of craving and impulsivity. This theoretical approach not only deepens our understanding of the neural and cognitive bases of addiction but also suggests novel intervention strategies. By recalibrating interoceptive predictions through targeted therapies, such as neuromodulation and mindfulness training, we can potentially restore the interoceptive accuracy, thereby offering new avenues for effective treatment of SUDs.

Resting state functional connectivity in adolescents with substance use disorder and their unaffected siblings

We aimed to examine resting-state functional connectivity (rsFC) in adolescents with substance use disorder (SUD) and their unaffected biological siblings (SIB), relative to typically-developing controls (TDC) in order to identify alterations in functional network organization that may be associated with the familial risk for SUD. Resting-state functional magnetic resonance imaging analysis included 20 adolescents with SUD, 20 SIB, and 18 TDC. Network-based analysis revealed that adolescents with SUD had significantly both weaker and higher rsFC compared to TDC mainly within the default-mode network (DMN) and between the DMN, fronto-parietal (FPN) and salience networks. In addition, adolescents with SUD showed lower rsFC between the visual network and other functional networks. Although the SIB group did not differ from TDC in the whole brain analysis, they showed lower rsFC within DMN and also between the visual network and other large-scale networks as well as higher rsFC between DMN and FPN compared to TDC in connections found to be abnormal in SUD group. Our results suggest that lower rsFC within DMN and higher rsFC between the DMN with FPN which were evident both in SUD and in SIB groups, and might be related to the familial predisposition for SUD.

Sex and hormonal effects on drug cue-reactivity and its regulation in human addiction

Objective

To study the sex and hormonal effects on cortico-striatal engagement during drug cue-reactivity and its regulation focusing on drug reappraisal.

Methods

Forty-nine men (age=41.96±9.71) with heroin use disorder (HUD) and 32 age-matched women (age=38.85±9.84) with HUD (n=16) or cocaine use disorder (CUD; n=16) were scanned using functional MRI, with a subgroup of women scanned twice, during the late-follicular and mid-luteal phases, to examine sex and menstrual phase differences in cortico-striatal drug cue-reactivity and its cognitive reappraisal and their correlations with ovarian hormones and drug craving.

Results

Women showed higher medial prefrontal cortex (PFC) drug cue-reactivity while men showed higher frontal eye field (FEF)/dorsolateral PFC (dlPFC) drug reappraisal as associated with lower cue-induced drug craving. In the women, drug cue-reactivity was higher during the follicular phase in the FEF/dlPFC, whereas drug reappraisal was higher during the luteal phase in the anterior PFC/orbitofrontal cortex. The more the estradiol during the follicular vs. luteal phase (Δ), the higher the Δdrug cue-reactivity in the vmPFC, which also correlated with higher Δdrug craving (observed also in the inferior frontal gyrus). The more this Δestradiol, the lower the Δdrug reappraisal in the vmPFC, anterior PFC and striatum. Conversely, Δprogesterone/estradiol ratio was positively associated with Δdrug reappraisal in the dlPFC.

Conclusions

Compared to men, women with addiction show more cortico-striatal reactivity to drug cue exposure and less PFC activity during drug reappraisal, driven by the follicular compared to luteal phase and directly related to craving and fluctuations in estrogen and progesterone with the former constituting a vulnerability and the latter a protective factor. This study provides insights for developing precisely timed and hormonally informed treatments for women with addiction.

Alterations of gray matter asymmetry in internet gaming disorder

Structural asymmetry is a subtle but pervasive property of the human brain, which has been found altered in various psychiatric and neurocognitive disorders. However, little is known regarding potential alterations of structural asymmetry underlying internet gaming disorder (IGD). Therefore, this study aimed to investigate the structural features of gray matter asymmetry in IGD. High-resolution structural magnetic resonance imaging data were collected from 104 individuals with IGD and 104 recreational game users (RGUs). We applied a whole-brain voxel-based asymmetry (VBA) approach to determine the asymmetrical aberrations of gray matter in relation to IGD. Furthermore, the local abnormalities of structural asymmetry were employed as features to examine the effect of classification using a support vector machine (SVM). The results indicated that individuals with IGD as compared to RGUs showed asymmetrical alterations of gray matter in the medial prefrontal cortex (mPFC), orbitofrontal cortex, precuneus, middle temporal gyrus, superior parietal lobule and inferior temporal gyrus, regions implicated in hedonic motivation, self-reflection, information integration and visuospatial attention processing. Moreover, these atypical asymmetrical features can distinguish IGD subjects from RGUs with high accuracy. These results suggested that disrupted structural asymmetry of motivational reward, visuospatial and default mode circuits might be potential biomarkers for identifying pathological gaming dependence. These findings extended our understanding of structural underpinnings of IGD and provided new insights for developing effective interventions to alleviate compulsive gaming usage.

Functional Connectivity Alterations in Cocaine Use Disorder: Insights from the Triple Network Model and the Addictions Neuroclinical Assessment Framework

Cocaine use disorder (CUD) disrupts functional connectivity within key brain networks, specifically the default mode network (DMN), salience network (SN), and central executive network (CEN). While the triple network model has been proposed to explain various psychiatric disorders, its applicability to CUD requires further exploration. In the present study, we built machine learning classifiers based on different combinations of DMN/SN/CEN to distinguish cocaine-use disorder (CUD) subjects from healthy control (HC) subjects. Among them, the combination of the SN and the CEN results in a remarkably high accuracy of 73.4% (sensitivity/specificity: 69.6%/78.6%, AUC: 0.78), outperforming the model based on the full triple network. This supports the hypothesis that during the binge/intoxication stage of addiction, the SN and the CEN play a more critical role than the DMN, consistent with the Addictions Neuroclinical Assessment (ANA) framework. Functional connectivity analysis revealed decreased connectivity within the DMN and the SN and increased connectivity within the CEN in CUD patients, suggesting that alterations in these networks could serve as biomarkers for addiction severity.

α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor density underlies intraregional and interregional functional centrality

Local and global functional connectivity densities (lFCD and gFCD, respectively), derived from functional magnetic resonance imaging (fMRI) data, represent the degree of functional centrality within local and global brain networks. While these methods are well-established for mapping brain connectivity, the molecular and synaptic foundations of these connectivity patterns remain unclear. Glutamate, the principal excitatory neurotransmitter in the brain, plays a key role in these processes. Among its receptors, the α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR) is crucial for neurotransmission, particularly in cognitive functions such as learning and memory. This study aimed to examine the association of the AMPAR density and FCD metrics of intraregional and interregional functional centrality. Using [11C]K-2, a positron emission tomography (PET) tracer specific for AMPARs, we measured AMPAR density in the brains of 35 healthy participants. Our findings revealed a strong positive correlation between AMPAR density and both lFCD and gFCD-lFCD across the entire brain. This correlation was especially notable in key regions such as the anterior cingulate cortex, posterior cingulate cortex, pre-subgenual frontal cortex, Default Mode Network, and Visual Network. These results highlight that postsynaptic AMPARs significantly contribute to both local and global functional connectivity in the brain, particularly in network hub regions. This study provides valuable insights into the molecular and synaptic underpinnings of brain functional connectomes.

Transformative impact of positive psychotherapy-based hope placement program on life goals and hope level of individuals with multiple sclerosis

AIM

This study aimed to assess the impact of a positive psychotherapy-based hope placement program on life goal setting and hope levels in individuals diagnosed with multiple sclerosis (MS).

METHOD

A Solomon Four-Group experimental design was used, involving 50 individuals diagnosed with MS who sought treatment at a university hospital's neurology outpatient clinic. Experimental (1-2) and control (1-2) groups were randomized, and pretests were administered exclusively to the experimental and control groups. Data were collected using a Personal Information Form, the Herth Hope Scale, and the Scale for Determining Life Goals in the Context of Positive Psychotherapy. A 5-week/10-session Positive Psychotherapy-Based Hope Placement Program was conducted online for the Experimental groups. The research was conducted in the form of group therapy. Post-tests were administered to all groups upon program completion.

RESULTS

The experimental 1-2 group exhibited statistically significant improvements in the Scale for Identifying Life Goals in the Context of Positive Psychotherapy and Herth Hope Scale scores (p < .05). The Positive Psychotherapy-Based Hope Placement Program effectively enhances hope levels and life goal setting for individuals diagnosed with MS.

CONCLUSION

The results indicate that the program increased the sense of purpose in life and elevated levels of hope among MS patients. These findings suggest that positive psychotherapy-based interventions significantly improve the quality of life for MS patients.

CLINICAL OR METHODOLOGICAL SIGNIFICANCE OF THIS ARTICLE

This study examines the impact of a Positive Psychotherapy-based hope placement program on determining hope and life purpose in patients with Multiple Sclerosis (MS). This research shows that HOPP (Hope Placement Program), an intervention based on Positive Psychotherapy, can significantly improve the quality of life of MS patients. These findings support the consideration of Positive Psychotherapy-based approaches as a potential therapeutic option that can positively influence the life experiences of MS patients. Therefore, this article makes an important contribution to researchers interested in using Positive Psychotherapy-based interventions in clinical practice and related research.

Transcranial Magnetic Stimulation Applications in the Study of Executive Functions: A Review

PURPOSE

Executive functions (EFs) are a set of advanced cognitive functions essential for human survival and behavioral regulation. Understanding neurophysiological mechanisms of EFs as well as exploring methods to enhance them are still challenging problems in cognitive neuroscience. In recent years, transcranial magnetic stimulation (TMS) has been widely used in the field of EF research and has made notable progress. This article aimed to discuss the impact of TMS technology on EF research from both basic and applied research perspectives.

METHODS

We searched for literature on TMS and EFs published in the last decade (2013-2023) and reviewed how TMS has been applied in the field of EF.

FINDINGS

We found that the combination of TMS with neuroimaging techniques was helpful in exploring the brain mechanisms of EFs and investigating the executive dysfunctions caused by other neuropsychiatric disorders. Moreover, TMS could be considered as one of the most important techniques to enhance EFs among patient populations, even healthy people, with high safety and credibility. Meanwhile, we discussed the application of TMS in the research of EFs and made suggestions for future research directions. We suggested that a multidisciplinary structure of methods such as epigenetics and endocrinology could be integrated with TMS for investigating deeper in EF domains, and a substantial number of high-quality clinical studies are required to further elucidate the effects of TMS on EFs.

CONCLUSIONS

TMS holds great promise for gaining insight into investigating the neural mechanisms of EFs and improving executive functions among different populations.

The distinct functional brain network and its association with psychotic symptom severity in men with methamphetamine-associated psychosis

BACKGROUND

Individuals using methamphetamine (METH) may experience psychosis, which usually requires aggressive treatment. Studies of the neural correlates of METH-associated psychosis (MAP) have focused predominantly on the default mode network (DMN) and cognitive control networks. We hypothesize that METH use alters global functional connections in resting-state brain networks and that certain cross-network connections could be associated with psychosis.

METHODS

We recruited 24 healthy controls (CRL) and 54 men with METH use disorder (MUD) who were then divided into 25 without psychosis (MNP) and 29 with MAP. Psychotic symptom severity was assessed using the Positive and Negative Syndrome Scale (PANSS), evaluating (1) large-scale alterations in regional-wise resting-state functional connectivity (rsFC) across 11 brain networks and (2) associations between rsFC and psychotic symptom severity.

RESULTS

The MUD group exhibited greater rsFC between the salience network (SN)-DMN, and subcortical network (SCN)-DMN compared to the CRL group. The MAP group exhibited decreased rsFC in the sensory/somatomotor network (SMN)-dorsal attention network (DAN), SMN-ventral attention network (VAN), SMN-SN, and SMN-auditory network (AN), whereas the MNP group exhibited increased rsFC in the SMN-DMN and the frontoparietal network (FPN)-DMN compared to CRL. Additionally, the MAP group exhibited decreased rsFC strength between the SMN-DMN, SMN-AN, SMN-FPN, and DMN-VAN compared to the MNP group. Furthermore, across the entire MUD group, the PANSS-Positive subscale was negatively correlated with the DMN-FPN and FPN-SMN, while the PANSS-Negative subscale was negatively correlated with the DMN-AN and SMN-SMN.

CONCLUSION

MUD is associated with altered global functional connectivity. In addition, the MAP group exhibits a different brain functional network compared to the MNP group.

Psychedelics as a potential treatment for tobacco use disorder: a systematic review

INTRODUCTION

Despite considerable efforts, tobacco use disorder persists as a significant public health issue. The effectiveness of current smoking cessation therapies is limited, leading to a growing interest in alternative treatment approaches such as psychedelics.

AIM

The aim of this review is to evaluate the scientific evidence regarding the role of psychedelics in smoking cessation.

METHODS

To identify relevant literature on psychedelics and smoking cessation, a search was conducted in four academic literature databases PubMed, MEDLINE, PsycINFO, and Embase. Databases were searched from their inception up to March 24, 2024.

RESULTS

Out of the 1073 articles identified in databases, 8 publications (both clinical and non-clinical studies) met the inclusion criteria, of which a total of 4 publications originated from a single study. The majority of the studies focused on psilocybin (n = 7), for which supportive evidence was suggested for the treatment of tobacco use disorder. Additionally, research was conducted with other psychedelics for smoking cessation, such as ayahuasca, mescaline, peyote, lysergic acid diethylamide (LSD), lysergic acid amide (LSA) and (dimethyltryptamine (DMT), but the evidence base for these psychedelics is too small to draw definitive conclusions.

CONCLUSIONS

There is, although limited, evidence that psychedelics, in particular psilocybin, may offer a potential avenue for combating tobacco use disorder, though more research is needed to understand their effectiveness and safety fully.

Sex-specific differences in brain activity dynamics of youth with a family history of substance use disorder

An individual's risk of substance use disorder (SUD) is shaped by a complex interplay of potent biosocial factors. Current neurodevelopmental models posit vulnerability to SUD in youth is due to an overreactive reward system and reduced inhibitory control. Having a family history of SUD is a particularly strong risk factor, yet few studies have explored its impact on brain function and structure prior to substance exposure. Herein, we utilized a network control theory approach to quantify sex-specific differences in brain activity dynamics in youth with and without a family history of SUD, drawn from a large cohort of substance-naïve youth from the Adolescent Brain Cognitive Development Study. We summarize brain dynamics by calculating transition energy, which probes the ease with which a whole brain, region or network drives the brain towards a specific spatial pattern of activation (i.e., brain state). Our findings reveal that a family history of SUD is associated with alterations in the brain's dynamics wherein: i) independent of sex, certain regions' transition energies are higher in those with a family history of SUD and ii) there exist sex-specific differences in SUD family history groups at multiple levels of transition energy (global, network, and regional). Family history-by-sex effects reveal that energetic demand is increased in females with a family history of SUD and decreased in males with a family history of SUD, compared to their same-sex counterparts with no SUD family history. Specifically, we localize these effects to higher energetic demands of the default mode network in females with a family history of SUD and lower energetic demands of attention networks in males with a family history of SUD. These results suggest a family history of SUD may increase reward saliency in males and decrease efficiency of top-down inhibitory control in females. This work could be used to inform personalized intervention strategies that may target differing cognitive mechanisms that predispose individuals to the development of SUD.

Altered Physiological, Affective, and Functional Connectivity Responses to Acute Stress in Patients With Alcohol Use Disorder

Background

There is evidence that the processing of acute stress is altered in alcohol use disorder (AUD), but little is known about how this is manifested simultaneously across different stress parameters and which neural processes are involved. The current study examined physiological and affective responses to stress and functional connectivity in AUD.

Methods

Salivary cortisol samples, pulse rate, and affect ratings were collected on 2 days from 34 individuals with moderate or severe AUD during early abstinence and 34 control participants. On one of the days, stress was induced, and on the other day, a nonstressful control task was performed. Following the intervention, participants underwent functional magnetic resonance imaging to assess functional connectivity, with a focus on cortical and subcortical seed regions previously reported to be involved in AUD and/or stress.

Results

For pulse rate and cortisol, stress responses were blunted in AUD, whereas the affective response was stronger. Neuroimaging analyses revealed stress-related group differences in functional connectivity, involving the connectivity of striatal seeds with the posterior default mode network, cerebellum, and midcingulate cortex and of the posterior default mode network seed with the striatum and thalamus.

Conclusions

The results suggest a dissociation between subjectively experienced distress and the physiological stress response in AUD as well as stress-related alterations in functional connectivity. These findings highlight the complex interplay between chronic alcohol use and acute stress regulation, offering valuable considerations for the development of therapeutic strategies.

Advancements in addressing drug dependence: A review of promising therapeutic strategies and interventions

Substance dependence represents a pervasive global concern within the realm of public health. Presently, it is delineated as a persistent and recurrent neurological disorder stemming from drug-triggered neuroadaptations in the brain's reward circuitry. Despite the availability of various therapeutic modalities, there has been a steady escalation in the mortality rate attributed to drug overdoses. Substantial endeavors have been directed towards the exploration of innovative interventions aimed at mitigating cravings and drug-induced repetitive behaviors. Within this review, we encapsulate the most auspicious contemporary treatment methodologies, accentuating meta-analyses of efficacious pharmacological and non-pharmacological approaches: including gabapentin, topiramate, prazosin, physical exercise regimens, and cerebral stimulation techniques.

Predicting the Hallucinogenic Potential of Molecules Using Artificial Intelligence

The development of new drugs addressing serious mental health and other disorders should avoid the psychedelic experience. Analogs of psychedelic drugs can have clinical utility and are termed "psychoplastogens". These represent promising candidates for treating opioid use disorder to reduce drug dependence, with rarely reported serious adverse effects. This drug abuse cessation is linked to the induction of neuritogenesis and increased neuroplasticity, a hallmark of psychedelic molecules, such as lysergic acid diethylamine. Some, but not all psychoplastogens may act through the G-protein coupled receptor (GPCR) 5HT2A whereas others may display very different polypharmacology making prediction of hallucinogenic potential challenging. In the process of developing tools to help design new psychoplastogens, we have used artificial intelligence in the form of machine learning classification models for predicting psychedelic effects using a published in vitro data set from PsychLight (support vector classification (SVC), area under the curve (AUC) 0.74) and in vivo human data derived from books from Shulgin and Shulgin (SVC, AUC, 0.72) with nested five-fold cross validation. We have also explored conformal predictors with ECFP6 and electrostatic descriptors in an effort to optimize them. These models have been used to predict known 5HT2A agonists to assess their potential to act as psychedelics and induce hallucinations for PsychLight (SVC, AUC 0.97) and Shulgin and Shulgin (random forest, AUC 0.71). We have tested these models with head twitch data from the mouse. This predictive capability is desirable to reliably design new psychoplastogens that lack in vivo hallucinogenic potential and help assess existing and future molecules for this potential. These efforts also provide useful insights into understanding the psychedelic structure activity relationship.

Brain dynamics supported by a hierarchy of complex correlation patterns defining a robust functional architecture

Functional magnetic resonance imaging (fMRI) provides insights into cognitive processes with significant clinical potential. However, delays in brain region communication and dynamic variations are often overlooked in functional network studies. We demonstrate that networks extracted from fMRI cross-correlation matrices, considering time lags between signals, show remarkable reliability when focusing on statistical distributions of network properties. This reveals a robust brain functional connectivity pattern, featuring a sparse backbone of strong 0-lag correlations and weaker links capturing coordination at various time delays. This dynamic yet stable network architecture is consistent across rats, marmosets, and humans, as well as in electroencephalogram (EEG) data, indicating potential universality in brain dynamics. Second-order properties of the dynamic functional network reveal a remarkably stable hierarchy of functional correlations in both group-level comparisons and test-retest analyses. Validation using alcohol use disorder fMRI data uncovers broader shifts in network properties than previously reported, demonstrating the potential of this method for identifying disease biomarkers.

Mapping functional traces of opioid memories in the rat brain

Addiction to psychoactive substances is a maladaptive learned behaviour. Contexts surrounding drug use integrate this aberrant mnemonic process and hold strong relapse-triggering ability. Here, we asked where context and salience might be concurrently represented in the brain during retrieval of drug-context paired associations. For this, we developed a morphine-conditioned place preference protocol that allows contextual stimuli presentation inside a magnetic resonance imaging scanner and investigated differences in activity and connectivity at context recall. We found context-specific responses to stimulus onset in multiple brain regions, namely, limbic, sensory and striatal. Differences in functional interconnectivity were found among amygdala, lateral habenula, and lateral septum. We also investigated alterations to resting-state functional connectivity and found increased centrality of the lateral septum in a proposed limbic network, as well as increased functional connectivity of the lateral habenula and hippocampal 'cornu ammonis' 1 region, after a protocol of associative drug-context. Finally, we found that pre- conditioned place preference resting-state connectivity of the lateral habenula and amygdala was predictive of inter-individual conditioned place preference score differences. Overall, our findings show that drug and saline-paired contexts establish distinct memory traces in overlapping functional brain microcircuits and that intrinsic connectivity of the habenula, septum, and amygdala likely underlies the individual maladaptive contextual learning to opioid exposure. We have identified functional maps of acquisition and retrieval of drug-related memory that may support the relapse-triggering ability of opioid-associated sensory and contextual cues. These findings may clarify the inter-individual sensitivity and vulnerability seen in addiction to opioids found in humans.

Alcohol, HMGB1, and Innate Immune Signaling in the Brain

PURPOSE

Binge drinking (i.e., consuming enough alcohol to achieve a blood ethanol concentration of 80 mg/dL, approximately 4-5 drinks within 2 hours), particularly in early adolescence, can promote progressive increases in alcohol drinking and alcohol-related problems that develop into compulsive use in the chronic relapsing disease, alcohol use disorder (AUD). Over the past decade, neuroimmune signaling has been discovered to contribute to alcohol-induced changes in drinking, mood, and neurodegeneration. This review presents a mechanistic hypothesis supporting high mobility group box protein 1 (HMGB1) and Toll-like receptor (TLR) signaling as key elements of alcohol-induced neuroimmune signaling across glia and neurons, which shifts gene transcription and synapses, altering neuronal networks that contribute to the development of AUD. This hypothesis may help guide further research on prevention and treatment.

SEARCH METHODS

The authors used the search terms "HMGB1 protein," "alcohol," and "brain" across PubMed, Scopus, and Embase to find articles published between 1991 and 2023.

SEARCH RESULTS

The database search found 54 references in PubMed, 47 in Scopus, and 105 in Embase. A total of about 100 articles were included.

DISCUSSION AND CONCLUSIONS

In the brain, immune signaling molecules play a role in normal development that differs from their functions in inflammation and the immune response, although cellular receptors and signaling are shared. In adults, pro-inflammatory signals have emerged as contributing to brain adaptation in stress, depression, AUD, and neurodegenerative diseases. HMGB1, a cytokine-like signaling protein released from activated cells, including neurons, is hypothesized to activate pro-inflammatory signals through TLRs that contribute to adaptations to binge and chronic heavy drinking. HMGB1 alone and in heteromers with other molecules activates TLRs and other immune receptors that spread signaling across neurons and glia. Both blood and brain levels of HMGB1 increase with ethanol exposure. In rats, an adolescent intermittent ethanol (AIE) binge drinking model persistently increases brain HMGB1 and its receptors; alters microglia, forebrain cholinergic neurons, and neuronal networks; and increases alcohol drinking and anxiety while disrupting cognition. Studies of human postmortem AUD brain have found elevated levels of HMGB1 and TLRs. These signals reduce cholinergic neurons, whereas microglia, the brain's immune cells, are activated by binge drinking. Microglia regulate synapses through complement proteins that can change networks affected by AIE that increase drinking, contributing to risks for AUD. Anti-inflammatory drugs, exercise, cholinesterase inhibitors, and histone deacetylase epigenetic inhibitors prevent and reverse the AIE-induced pathology. Further, HMGB1 antagonists and other anti-inflammatory treatments may provide new therapies for alcohol misuse and AUD. Collectively, these findings suggest that restoring the innate immune signaling balance is central to recovering from alcohol-related pathology.

Disrupted dynamic brain functional connectivity in male cocaine use disorder: Hyperconnectivity, strongly-connected state tendency, and links to impulsivity and borderline traits

Cocaine use is a major public health problem with serious negative consequences at both the individual and societal levels. Cocaine use disorder (CUD) is associated with cognitive and emotional impairments, often manifesting as alterations in brain functional connectivity (FC). This study employed resting-state functional magnetic resonance imaging (rs-fMRI) to examine dynamic FC in 38 male participants with CUD and 31 matched healthy controls. Using group spatial independent component analysis (group ICA) combined with sliding window approach, we identified two recurring distinct connectivity states: the strongly-connected state (state 1) and weakly-connected state (state 2). CUD patients exhibited significant increased mean dwell and fraction time in state 1, and increased transitions from state 2 to state 1, demonstrated significant strongly-connected state tendency. Our analysis revealed abnormal FC patterns that are state-dependent and state-shared in CUD patients. This study observed hyperconnectivity within the default mode network (DMN) and between DMN and other networks, which varied depending on the state. Furthermore, after adjustment for multiple comparisons, we found significant correlations between these altered dynamic FCs and clinical measures of impulsivity and borderline personality disorder. The disrupted FC and repetitive effects of precuneus and angular gyrus across correlations suggested that they might be the important hub of neural circuits related behaviorally and mentally in CUD. In summary, our study highlighted the potential of these disrupted FC as neuroimaging biomarkers and therapeutic targets, and provided new insights into the understanding of the neurophysiologic mechanisms of CUD.

Transcranial magnetic stimulation for methamphetamine use disorder: A scoping review within the neurocircuitry model of addiction

The use of methamphetamine in the United States is increasing, contributing now to the "fourth wave" in the national opioid epidemic crisis. People who suffer from methamphetamine use disorder (MUD) have a higher risk of death. No pharmacological interventions are approved by the FDA and psychosocial interventions are only moderately effective. Transcranial Magnetic Stimulation (TMS) is a relatively novel FDA-cleared intervention for the treatment of Major Depressive Disorder (MDD) and other neuropsychiatric conditions. Several lines of research suggest that TMS could be useful for the treatment of addictive disorders, including MUD. We will review those published clinical trials that show potential effects on craving reduction of TMS when applied over the dorsolateral prefrontal cortex (DLPFC) also highlighting some limitations that affect their generalizability and applicability. We propose the use of the Koob and Volkow's neurocircuitry model of addiction as a frame to explain the brain effects of TMS in patients with MUD. We will finally discuss new venues that could lead to a more individualized and effective treatment of this complex disorder including the use of neuroimaging, the exploration of different areas of the brain such as the frontopolar cortex or the salience network and the use of biomarkers.

Intrinsic connectivity demonstrates a shared role of the posterior cingulate for cue reactivity in both gambling and cocaine use disorders

Cue reactivity is relevant across addictive disorders as a process relevant to maintenance, relapse, and craving. Understanding the neurobiological foundations of cue reactivity across substance and behavioral addictions has important implications for intervention development. The present study used intrinsic connectivity distribution methods to examine functional connectivity during a cue-exposure fMRI task involving gambling, cocaine and sad videos in 22 subjects with gambling disorder, 24 with cocaine use disorder, and 40 healthy comparison subjects. Intrinsic connectivity distribution implicated the posterior cingulate cortex (PCC) at a stringent whole-brain threshold. Post-hoc analyses investigating the nature of the findings indicated that individuals with gambling disorder and cocaine use disorder exhibited decreased connectivity in the posterior cingulate during gambling and cocaine cues, respectively, as compared to other cues and compared to other groups. Brain-related cue reactivity in substance and behavioral addictions involve PCC connectivity in a content-to-disorder specific fashion. The findings suggesting that PCC-related circuitry underlies cue reactivity across substance and behavioral addictions suggests a potential biomarker for targeting in intervention development.

Altered intrinsic neural timescales and neurotransmitter activity in males with tobacco use disorder

Previous researches of tobacco use disorder (TUD) has overlooked the hierarchy of cortical functions and single modality design separated the relationship between macroscopic neuroimaging aberrance and microscopic molecular basis. At present, intrinsic timescale gradient of TUD and its molecular features are not fully understood. Our study recruited 146 male subjects, including 44 heavy smokers, 50 light smokers and 52 non-smokers, then obtained their rs-fMRI data and clinical scales related to smoking. Intrinsic neural timescale (INT) method was performed to describe how long neural information was stored in a brain region by calculating the autocorrelation function (ACF) of each voxel to examine the difference in the ability of information integration among the three groups. Then, correlation analyses were conducted to explore the relationship between INT abnormalities and clinical scales of smokers. Finally, cross-modal JuSpace toolbox was used to investigate the association between INT aberrance and the expression of specific receptor/transporters. Compared to healthy controls, TUD subjects displayed decreased INT in control network (CN), default mode network (DMN), sensorimotor areas and visual cortex, and such trend of decreasing INT was more pronounced in heavy smokers. Moreover, various neurotransmitters (including dopaminergic, acetylcholine and μ-opioid receptors) were involved in the molecular mechanism of timescale decreasing and differed in heavy and light smokers. These findings supplied novel insights into the brain functional aberrance in TUD from an intrinsic neural dynamic perspective and confirm INT was a potential neurobiological marker. And also established the connection between macroscopic imaging aberrance and microscopic molecular changes in TUD.

Altered executive control network and default model network topology are linked to acute electronic cigarette use: A resting-state fNIRS study

In recent years, electronic cigarettes (e-cigs) have gained popularity as stylish, safe, and effective smoking cessation aids, leading to widespread consumer acceptance. Although previous research has explored the acute effects of combustible cigarettes or nicotine replacement therapy on brain functional activities, studies on e-cigs have been limited. Using fNIRS, we conducted graph theory analysis on the resting-state functional connectivity of 61 male abstinent smokers both before and after vaping e-cigs. And we performed Pearson correlation analysis to investigate the relationship between alterations in network metrics and changes in craving. E-cig use resulted in increased degree centrality, nodal efficiency, and local efficiency within the executive control network (ECN), while causing a decrease in these properties within the default model network (DMN). These alterations were found to be correlated with reductions in craving, indicating a relationship between differing network topologies in the ECN and DMN and decreased craving. These findings suggest that the impact of e-cig usage on network topologies observed in male smokers resembles the effects observed with traditional cigarettes and other forms of nicotine delivery, providing valuable insights into their addictive potential and effectiveness as aids for smoking cessation.