tDCS in Addiction and Impulse Control Disorders

Non-invasive suppression of the human nucleus accumbens (NAc) with transcranial focused ultrasound (tFUS) modulates the reward network: a pilot study

Background

The nucleus accumbens (NAc) is a key node of the brain reward circuit driving reward-related behavior. Dysregulation of NAc has been demonstrated to contribute to pathological markers of addiction in substance use disorder (SUD) making it a potential therapeutic target for brain stimulation. Transcranial focused ultrasound (tFUS) is an emerging non-invasive brain stimulation approach that can modulate deep brain regions with a high spatial resolution. However, there is currently no evidence showing how the brain activity of NAc and brain functional connectivity within the reward network neuromodulated by tFUS on the NAc.

Methods

In this pilot study, we carried out a single-blind, sham-controlled clinical trial using functional magnetic resonance imaging (fMRI) to investigate the underlying mechanism of tFUS neuromodulating the reward network through NAc in ten healthy adults. Specifically, the experiment consists of a 20-min concurrent tFUS/fMRI scan and two 24-min resting-state fMRI before and after the tFUS session.

Results

Firstly, our results demonstrated the feasibility and safety of 20-min tFUS on NAc. Additionally, our findings demonstrated that bilateral NAc was inhibited during tFUS on the left NAc compared to sham. Lastly, increased functional connectivity between the NAc and medial prefrontal cortex (mPFC) was observed after tFUS on the left NAc, but no changes for the sham group.

Conclusion

Delivering tFUS to the NAc can modulate brain activations and functional connectivity within the reward network. These preliminary findings suggest that tFUS could be potentially a promising neuromodulation tool for the direct and non-invasive management of the NAc and shed new light on the treatment for SUD and other brain diseases that involve reward processing.

Transcranial Direct Current Stimulation Decreases P3 Amplitude and Inherent Delta Activity during a Waiting Impulsivity Paradigm: Crossover Study

The inability to wait for a target before initiating an action (i.e., waiting impulsivity) is one of the main features of addictive behaviors. Current interventions for addiction, such as transcranial Direct Current Stimulation (tDCS), have been suggested to improve this inability. Nonetheless, the effects of tDCS on waiting impulsivity and underlying electrophysiological (EEG) markers are still not clear. Therefore, this study aimed to evaluate the effects of neuromodulation over the right inferior frontal gyrus (rIFG) on the behavior and EEG markers of reward anticipation (i.e., cue and target-P3 and underlying delta/theta power) during a premature responding task. For that, forty healthy subjects participated in two experimental sessions, where they received active and sham tDCS over the rIFG combined with EEG recording during the task. To evaluate transfer effects, participants also performed two control tasks to assess delay discounting and motor inhibition. The active tDCS decreased the cue-P3 and target-P3 amplitudes, as well as delta power during target-P3. While no tDCS effects were found for motor inhibition, active tDCS increased the discounting of future rewards when compared to sham. These findings suggest a tDCS-induced modulation of the P3 component and underlying oscillatory activity during waiting impulsivity and the discounting of future rewards.

Effects of psychoeducation combined with transcranial direct current stimulation on reducing cigarette craving and consumption in male smokers

Psychoeducation (PE) has been widely used in smoking interventions, but its long-term effects are limited. Recent studies have reported that, in some fields, a combination of transcranial direct current stimulation (tDCS) and cognitive training (e.g., working memory tasks) may improve cognitive outcomes; thus, we aimed to investigate whether such a combined intervention has a better effect than a PE intervention for reducing smoking cravings and cigarette consumption. In Exp. 1, 19 male smokers received four types of interventions at one-week intervals. In each session, participants were presented with audio PE (or control) while receiving 2-mA active (or sham) tDCS of the dorsolateral prefrontal cortex (DLPFC). In Exp. 2, 48 male smokers were randomized into four experimental groups (PE + Active, Control + Active, PE + Sham, or Control + Sham). Each participant received one type of five-day intervention (i.e., watching a five-minute PE/Control video twice while receiving 2-mA active/sham tDCS) and was followed up for one week. The results showed (a) an enhancement effect of tDCS on PE's ability to reduce cigarette consumption; (b) that repeated PE has a cumulative effect on reducing both craving and cigarette consumption during the intervention period; and (c) that, compared with PE alone, PE combined with tDCS is capable of helping participants maintain a low intake of cigarettes over one week. These findings suggest that repeated interventions of PE combined with tDCS may be effective in reducing smoking consumption and that further studies are warranted to confirm its application.

Transcranial Electrical Neurostimulation as a Potential Addiction Treatment

Addiction remains difficult to treat, but non-invasive transcranial electrical and magnetic neurostimulation methods may provide promising and cost-effective treatment approaches. We provide a narrative review of recent developments and evidence of effectiveness and consider newer technology that may yield improved treatment approaches. In particular, we review temporal interference electrical neurostimulation, which allows non-invasive and focal stimulation of deep brain regions. This provides a promising new potential approach to treat addiction, because many of the brain regions that seem most important for addiction are deeper in the brain, out of reach of existing technologies such as transcranial direct current stimulation.

The efficacy of neurofeedback for alcohol use disorders - a systematic review

BACKGROUND

Alcoholism is a serious social, economic and public health problem. Alcoholism can affect the gastrointestinal, neurological, cardiovascular and respiratory systems, and it can be fatal, costing the healthcare system huge amounts of money. Despite the availability of cognitive-behavioural and psychosocial therapies, alcoholism has a high recurrence rate and a dismal prognosis, with a wide inter-individual variation. As a result, better or adjuvant therapies that improve or facilitate alcoholism therapy are required. We conducted a systematic review to look into the published studies that reported the effectiveness of non-pharmacological neurofeedback (NF) interventions in patients with alcohol use disorders (AUDs).

METHODS

PubMed, Google Scholar, The Cochrane Library, Science Direct and Clinicaltrial.gov were searched until 4 April 2022. Original articles of any design reporting on the use of NF approaches in the treatment of AUDs were included. Information related to study design, participants, control group, neuromodulation therapy, number of sessions and key findings of the study were extracted. The Joanna Briggs Institute's (JBI) Critical Appraisal Checklist for Studies was used to assess the quality of studies.

RESULTS

A total of 20 research articles (including 618 participants) were retrieved and included for qualitative analysis. The sample size ranged from 1 (case report) to 80, with years of publication ranging from 1977 to 2022. Nine of the 20 articles included in the study were conducted in the United States, followed by Germany, the United Kingdom, India, the Netherlands and South Korea. Out of the 20 studies included, 8 (40%) had a moderate risk of bias, while the other, i.e. 60% had a low risk of bias. The effectiveness of various neurological treatments in the treatment of AUDs was established in these 20 studies. There have been 11 studies on EEG NF training, three studies on real-time FMRI NF, two studies each on transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS), and one study each on deep brain stimulation (DBS) and theta burst stimulation (TBS). These alternative neurological therapies have been demonstrated to lower alcohol cravings and consumption temporarily, reduce anxiety and depression scores, reduce relapse rates and increase control of brain activity.

CONCLUSIONS

The use of various neuromodulation approaches to the treatment of AUD shows promise. However, more research with larger sample size is required.

Food Addiction Problems in College Students: The Relationship between Weight-Related Variables, Eating Habits, and Food Choices

The concept of food addiction, characterized by a strong urge to overeat highly palatable foods, has gained increased research attention over the last decade. College students are a recognized risk group for manifesting an eating pathology and weight gain due to the changes in eating habits experienced during this period. However, there is a gap in the literature connecting food addiction with eating and weight variables in this population. Thus, the present study aims to characterize food addiction in a sample of college students and enlighten the relationship between food addiction, weight-variables, eating habits, and food choices in this population. A sample of 194 college students (89.2% females) aged between 18 and 32 years old (M = 20.85, SD = 2.78) completed a set of self-reported online questionnaires on Google Forms. Namely, a Sociodemographic and Anthropometric Questionnaire, a questionnaire on Food Choices Characterization, the Eating Habits Scale, and the Portuguese Yale Food Addiction Scale 2.0. Thirty (22.2%) participants presented food addiction problems. The logistic regression models utilized suggest that participants in the group with food addiction problems are more likely to seek clinical help to control weight, to consider that they should eat less food high in sugar, and to report lower food adequacy. In sum, this finding highlighted a connection between food addiction, weight dissatisfaction, eating habits, and food choices in college students, a population at risk for developing and retaining eating pathologies. Further research is essential to evaluate and implement interventions regarding food addiction, weight dissatisfaction, eating habits, and food choices in college students.

Neural cue-reactivity in pathological gambling as evidence for behavioral addiction: a systematic review

Increasing incidence of problem gambling has led to prioritizing the problem from the point of view of public health. Additionally, gambling disorder has been recently classified as a behavioral addiction, with implications for both its diagnosis and treatment. However, the shared neural substrate of addictions, to substances and behavioral, is still discussed. Thus, this systematic review aims to provide up-to-date knowledge from the past five years (2017-2022) concerning the neural correlates of gambling related stimuli (cue-reactivity) on the basis of a previous review (Brevers et al., Cognitive, Affective and Behavioral Neuroscience 18:718-729, 2019). A total of five studies were included in the review. Activation of brain areas related to memory, reward and executive functions could be the underlying mechanism of this behavioral addiction. Specifically, nucleus accumbens and striatum (ventral and dorsal), parahippocampal regions, the right amygdala and several prefrontal cortex regions have systematically been found more active in those subjects exposed to gambling-related cues. Also, the insula could play a pivotal role connecting these three systems in a highly integrated neural network with several implications for reward processing modulation, associative learning and top-down attentional regulation to improve saliency of addiction-related cues. These results are consistent with previous findings on other substance addictions, such as alcohol, tobacco, marijuana or cocaine. The study of neural reactivity to stimuli related to addiction could be useful as a biomarker of the severity of the disorder, the efficacy of the treatment, the risk of relapse, in addition to being an objective criterion to measure the effectiveness of prevention campaigns.

Non-invasive brain stimulation for osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease, the prevalence of OA is increasing, and the elderly are the most common in patients with OA. OA has a severe impact on the daily life of patients, this increases the demand for treatment of OA. In recent years, the application of non-invasive brain stimulation (NIBS) has attracted extensive attention. It has been confirmed that NIBS plays an important role in regulating cortical excitability and oscillatory rhythm in specific brain regions. In this review, we summarized the therapeutic effects and mechanisms of different NIBS techniques in OA, clarified the potential of NIBS as a treatment choice for OA, and provided prospects for further research in the future.

How Should Transcranial Direct Current Stimulation be Used in Populations With Severe Alcohol Use Disorder? A Clinically Oriented Systematic Review

Background and rationale. Severe alcohol use disorder (SAUD) is a major public health concern, given its massive individual, interpersonal, and societal consequences. The available prevention and treatment programs have proven limited effectiveness, as relapse rates are still high in this clinical population. Developing effective interventions reducing the appearance and persistence of SAUD thus constitutes an experimental and clinical priority. Among the new therapeutic approaches, there is a growing interest for noninvasive neuromodulation techniques, and particularly for transcranial direct current stimulation (tDCS) as an adjunctive treatment in neuropsychiatric disorders, including SAUD. Methods. We propose a systematic review, based on preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, evaluating the available evidence on the effectiveness of tDCS to improve clinical interventions in SAUD. Results. We provide an integrative overview of studies applying tDCS in clinical populations with SAUD, together with a standardized methodological quality assessment. We show that the currently available data remain inconsistent. Some data suggested that tDCS can (1) reduce craving, relapse or alcohol-cue reactivity and (2) improve cognitive control and inhibition. However, other studies did not observe any beneficial effect of tDCS in SAUD. Conclusions. Capitalizing on the identified strengths and shortcomings of available results, we present evidence-based clinical guidelines to integrate tDCS in current clinical settings and to combine it with neurocognitive training.

An Automated Workflow for the Electric Field Modeling of High-definition Transcranial Direct Current Stimulation (HD-tDCS) in Chronic Stroke with Lesions

Transcranial Direct Current Stimulation is a popular noninvasive brain stimulation (NIBS) technique that modulates brain excitability by means of low-amplitude electrical current (usually <4mA) delivered to the electrodes on the scalp. The NIBS research has gained significant momentum in the past decade, prompting tDCS as an adjunctive therapeutic tool for neuromuscular disorders like stroke. However, due to stroke lesions and the differences in individual neuroanatomy, the targeted brain region may not show the same response upon NIBS across stroke patients. To this end, we conducted a study to test the feasibility of targeted NIBS. The hand motor hotspot (HMH) for each chronic stroke participant was identified using Neuronavigated Transcranial Magnetic Stimulation (TMS). After identifying the HMH as the neural target site, we applied High-definition TDCS with the current delivered at 2mA for 20 minutes. To simulate the effects of HD-tDCS in the brain, especially with stroke lesions, we used the computational modeling tool (ROAST). The lesion mask was identified using an automated tool (LINDA). This paper demonstrates that the stroke lesions can be incorporated in the computational modeling of electric field distribution upon HD-tDCS without manual intervention.

Transcranial direct current stimulation of the prefrontal cortex reduces cigarette craving in not motivated to quit smokers: A randomized, sham-controlled study

Transcranial direct current stimulation (tDCS) over the dorsolaterateral prefrontal cortex (DLPFC) has been indicated as a promising treatment for several addictions, while its contribution for smoking cessation was less investigated. In particular, the role of motivation to quit and the nicotine dependence level as possible mediators of tDCS effect needs to be deepened. In the present study, we recruited twenty smokers who did not look for a treatment to quit: most of them presented a mild level of nicotine addiction, and they were randomly assigned to active or sham group for receiving bilateral tDCS over the DLPFC. tDCS was provided for five consecutive days with anode over the right hemisphere: in the first and the last day the craving level was evaluated through a specific evoking procedure, and the daily cigarette consumption was recorded. Results showed that the active tDCS decreased by about 50% the cigarette craving, while the number of cigarettes smoked remained unchanged and no differences emerged in the sham group. The present study indicates the tDCS of the DLPFC as a possible treatment for smoking addiction because of its effectiveness in reducing craving. Further, as we recruited smokers with no motivation to quit, and the nicotine dependence level was a moderator of the tDCS effect, we suggest that its efficacy might be even greater in the severe smokers looking for a treatment.

Transcranial electrostimulation with special waveforms enhances upper-limb motor function in patients with chronic stroke: a pilot randomized controlled trial

Background

Transcranial direct current stimulation (tDCS) and intermittent theta burst stimulation (iTBS) were both demonstrated to have therapeutic potentials to rapidly induce neuroplastic effects in various rehabilitation training regimens. Recently, we developed a novel transcranial electrostimulation device that can flexibly output an electrical current with combined tDCS and iTBS waveforms. However, limited studies have determined the therapeutic effects of this special waveform combination on clinical rehabilitation. Herein, we investigated brain stimulation effects of tDCS-iTBS on upper-limb motor function in chronic stroke patients.

Methods

Twenty-four subjects with a chronic stroke were randomly assigned to a real non-invasive brain stimulation (NIBS; who received the real tDCS + iTBS output) group or a sham NIBS (who received sham tDCS + iTBS output) group. All subjects underwent 18 treatment sessions of 1 h of a conventional rehabilitation program (3 days a week for 6 weeks), where a 20-min NIBS intervention was simultaneously applied during conventional rehabilitation. Outcome measures were assessed before and immediately after the intervention period: Fugl-Meyer Assessment-Upper Extremity (FMA-UE), Jebsen-Taylor Hand Function Test (JTT), and Finger-to-Nose Test (FNT).

Results

Both groups showed improvements in FMA-UE, JTT, and FNT scores after the 6-week rehabilitation program. Notably, the real NIBS group had greater improvements in the JTT (p = 0. 016) and FNT (p = 0. 037) scores than the sham NIBS group, as determined by the Mann–Whitney rank-sum test.

Conclusions

Patients who underwent the combined ipsilesional tDCS-iTBS stimulation with conventional rehabilitation exhibited greater impacts than did patients who underwent sham stimulation-conventional rehabilitation in statistically significant clinical responses of the total JTT time and FNT after the stroke. Preliminary results of upper-limb functional recovery suggest that tDCS-iTBS combined with a conventional rehabilitation intervention may be a promising strategy to enhance therapeutic benefits in future clinical settings.

Trial registration: ClinicalTrials.gov Identifier: NCT04369235. Registered on 30 April 2020.

Transcranial Direct Current Stimulation Combined With Cognitive Training Induces Response Inhibition Facilitation Through Distinct Neural Responses According to the Stimulation Site: A Follow-up Event-Related Potentials Study

OBJECTIVE

We investigated whether the mid-term impact (1 week posttraining) of a "combined cognitive rehabilitation (CRP)/transcranial direct current stimulation (tDCS) program" on the performance of a Go/No-go task was enhanced compared with isolated CRP and whether it varied according to the stimulation site (right inferior frontal gyrus [rIFG] vs right dorsolateral prefrontal cortex [rDLPFC]).

METHODS

A total of 150 healthy participants were assigned to (1) an Inhibition Training (IT) group, (2) a group receiving active tDCS over the rIFG in combination with IT (IT + IF), (3) a group receiving active tDCS over the rDLPFC in combination with IT (IT + DL), (4) a group receiving IT with sham tDCS (ITsham), and (5) a No-Training (NT) group to control for test-retest effects. Each group undertook 3 sessions of a Go/No-go task concomitant with the recording of event-related potentials (T0, before training; T1, at the end of a 4-day training session [20 minutes each day]; T2, 1 week after T1).

RESULTS

With the exception of the NT participants, all the groups exhibited improved performances at T2. The IT + DL group exhibited the best improvement profile, indexed by faster response times (RTs) (T0 > T1 = T2), with a reduced rate of errors at the posttraining sessions compared with both T0 and T1. This "inhibitory learning effect" was neurophysiologically indexed by shorter No-go N2d latencies and enhanced No-go P3d amplitudes.

CONCLUSION

CRP combined with active tDCS over the rDLPFC appears to be optimal for boosting long-term (one week) inhibitory skills as it induced specific and robust neural changes.

Multi-session electrical neuromodulation effects on craving, relapse and cognitive functions in cocaine use disorder: A randomized, sham-controlled tDCS study

BACKGROUND

The use of transcranial Direct Current Stimulation (tDCS) has previously shown promising results for reducing craving in cocaine use disorder. In this study we further explored the potential of tDCS as add-on intervention in the treatment of cocaine use disorder.

METHODS

In a randomized, placebo-controlled, between subject study, we applied tDCS bilaterally with the anodal electrode targeting the right dorsolateral prefrontal cortex (DLPFC; https://clinicaltrials.gov/ct2/show/NCT03025321). Patients with cocaine use disorder were allocated to ten sessions of either active tDCS (n = 29) or sham (n = 30) on five consecutive days. Inhibitory control and risky decision-making were measured via a Go-NoGo task and a two-choice gambling task, respectively, each at baseline, one day after all tDCS sessions and after three months. Relapse at follow-up and craving were also assessed.

RESULTS

There was no significant effect of active tDCS on the number of cocaine use days and craving. Relapse was frequent among patients who had received either active or sham tDCS (48.0 % and 69.2 %, respectively), despite an overall decrease in craving during the first two weeks of treatment. No effects were found on cognitive functions. An exploratory analysis for crack cocaine use only revealed that relapse rates were significantly reduced after active tDCS (n = 17) as compared to sham (n = 19).

CONCLUSIONS

No beneficial effects of tDCS on number of cocaine use days, craving and cognitive functions were found in the present study, but somewhat promising results were obtained regarding relapse rates among crack-cocaine users specifically. Further research is required to determine the efficacy of tDCS as a complementary treatment in cocaine use disorder.

Delivering Transcranial Direct Current Stimulation Away From Clinic: Remotely Supervised tDCS

INTRODUCTION

To demonstrate the broad utility of the remotely supervised transcranial direct current stimulation (RS-tDCS) protocol developed to deliver at-home rehabilitation for individuals with multiple sclerosis (MS).

METHODS

Stimulation delivered with the RS-tDCS protocol and paired with adaptive cognitive training was delivered to three different study groups of MS patients to determine the feasibility and tolerability of the protocol. The three studies each used consecutively increasing amounts of stimulation amperage (1.5, 2.0, and 2.5 mA, respectively) and session numbers (10, 20, and 40 sessions, respectively).

RESULTS

High feasibility and tolerability of the stimulation were observed for n = 99 participants across three tDCS pilot studies.

CONCLUSIONS

RS-tDCS is feasible and tolerable for MS participants. The RS-tDCS protocol can be used to reach those in locations without clinic access and be paired with training or rehabilitation in locations away from the clinic. This protocol could be used to deliver tDCS paired with training or rehabilitation activities remotely to service members and veterans.

Change in core symptoms of borderline personality disorder by tDCS: A pilot study

Borderline personality disorder (BPD) recognizes several psychopathological dimensions related to prefrontal cortex impairments. Transcranial Direct Current Stimulation (tDCS) targeting the right prefrontal dorsolateral cortex (DLPFC) positively influence cognitive functions related to impulsivity in healthy subjects. A randomized double-blind study was designed to investigate whether tDCS could modulate core dimensions (impulsivity, aggression, affective dysregulation) of BPD. Also effects on decision making process and substances craving was assessed. Patients were randomized to receive active-tDCS at 2 mA versus sham-tDCS, once a day for 15 sessions. Anode was placed on the right DLPFC (F4), cathode on the left DLPFC (F3). Impulsivity and aggression measures were significantly reduced only in patients treated with active-tDCS. Decision-making process was marginally influenced by the active current. Craving intensity was reduced only in the active-tDCS sample. Both groups showed improvements in the affective dysregulation dimension and anxious and depressive symptoms. The application of bilateral tDCS targeting right DLPFC with anodal stimulation seems to improve core dimensions of BPD (mainly impulsivity and aggression) probably by restoring prefrontal activity. tDCS might be a potential tool for preventing self-harming behaviors.

Effect of prefrontal tDCS on resting brain fMRI graph measures in Alcohol Use Disorders: A randomized, double-blind, sham-controlled study

OBJECTIVES

Transcranial Direct Current Stimulation (tDCS) is a promising new adjuvant approach in the treatment of Alcohol Use Disorders (AUDs) that has the potential to ameliorate the aberrations secondary to chronic alcohol use. In this study, using a randomized, double-blind, sham-controlled, parallel-arm design, we examined the effects of prefrontal tDCS on resting-state functional magnetic resonance imaging (rsfMRI) and its correlates with impulsivity and time to first lapse in subjects with AUDs.

METHODS

Patients with AUD as per DSM-5 criteria were randomly allocated to receive a five-day course of either verum-tDCS (n = 12) or sham-tDCS (n = 12). Of them, 21 patients (verum/sham = 11/10) participated in both baseline and post-intervention 10-min rsfMRI sessions. Outside the scanner, subjects also performed the Stop-Signal Task at two time-points (baseline and post-intervention), which provided a measure of changes in impulsivity following tDCS. After completion of the post-intervention scan, all subjects were discharged and were followed-up for 90 days post-discharge or until lapse to first alcohol use.

RESULTS

Graph theoretical analysis of rsfMRI data revealed that verum-tDCS (but not sham) resulted in a significant increase in the global efficiency of brain networks with a concurrent significant reduction in global clustering; network-based statistical analysis identified a significant increase in the functional connectivity of a specific sub-network involving prefrontal regions. Furthermore, increased global efficiency of brain networks following verum tDCS predicted a significantly reduced likelihood of relapse. In addition, a reduction in the global clustering had a significant positive correlation with a reduction in the measure of impulsivity.

CONCLUSIONS

The present study adds further support to the increasing evidence base for the clinical utility of tDCS in AUDs. Importantly, we observed improvement in both whole-brain network efficiency as well as inter-regional connectivity within a specific local prefrontal sub-network that is relevant to the neurobiology of AUDs. Replication and extension of these promising leads from the present study can facilitate clinical translation of tDCS, given its advantages (i.e. safety, cost-effectiveness, administration ease with potential for remotely-supervised / home-based application) for treating patients with AUDs.

No effect of repetitive tDCS on daily smoking behaviour in light smokers: A placebo controlled EMA study

Introduction

The effectiveness of repetitive transcranial Direct Current Stimulation (tDCS) on reducing smoking behaviour has been studied with mixed results. Smoking behaviour is influenced by affect and context, therefore we choose to use mobile ecological momentary assessments (EMA) to measure changes in smoking behaviour after tDCS.

Methods

In a randomized, placebo-controlled, between subject study, we applied tDCS bilaterally with the anodal electrode targeting the right DLPFC (https://clinicaltrials.gov/ct2/show/NCT03027687). Smokers were allocated to six sessions of either active tDCS (n = 35) or sham tDCS (n = 36) and received two sessions on three different days in one week. They were asked to keep track of their daily cigarette consumption, craving and affect in an application on their mobile phones for three months starting one week before the first tDCS session.

Results

Number of smoked cigarettes a day progressively decreased up to one week after the last tDCS session in both conditions. Active treatment had no additional effect on cigarette consumption, craving and affect.

Conclusions

In this exploratory study, repetitive bilateral tDCS over the DLPFC had no effect on daily smoking behaviour. Future research needs to investigate how motivation to quit smoking and the number of tDCS sessions affect the efficacy of repetitive tDCS.

Cognition and addiction

In this targeted review, we summarize current knowledge on substance-use disorder (SUD)-related cognitive deficits, the link between these deficits and clinical outcomes, and the cognitive training, remediation, and pharmacological approaches that have the potential to rescue cognition. We conclude that: (i) people with SUDs have moderate deficits in memory, attention, executive functions, and decision-making (including reward expectancy, valuation, and learning); (ii) deficits in higher-order executive functions and decision-making are significant predictors of relapse; (iii) cognitive training programs targeting reward-related appetitive biases, cognitive remediation strategies targeting goal-based decision-making, and pharmacotherapies targeting memory, attention, and impulsivity have potential to rescue SUD-related cognitive deficits. We suggest avenues for future research, including developing brief, clinically oriented harmonized cognitive testing suites to improve individualized prediction of treatment outcomes; computational modeling that can achieve deep phenotyping of cognitive subtypes likely to respond to different interventions; and phenotype-targeted cognitive, pharmacological, and combined interventions. We conclude with a tentative model of neuroscience-informed precision medicine.


Brain Stimulation to Modulate Food Intake and Eating Behavior

PURPOSE OF REVIEW

Appetitive behaviors are mediated through homeostatic and reward signaling of brain circuits. There has been increasing interest in the use of neuromodulation techniques aimed at targeting brain regions such as the lateral prefrontal and subcortical regions associated with dysregulation of eating behaviors.

RECENT FINDINGS

Invasive brain stimulation techniques have demonstrated promising results in treating severe and enduring anorexia nervosa and morbid obesity. In addition, non-invasive techniques have been shown to successfully reduce food craving, hunger ratings, and calorie intake as well as binge/purge symptoms in eating disorders. Brain stimulation offers promising results for treating symptoms associated with eating disorders and modifying appetitive behaviors including craving and caloric consumption. Future research should focus on identifying optimal frequency and duration of stimulation and employ longitudinal studies to assess long-term effectiveness on clinical outcomes such as eating disorder symptomatology, weight loss, and sustained improvements in eating behaviors over time.

Transcranial Direct Current Stimulation on Opium Craving, Depression, and Anxiety: A Preliminary Study

OBJECTIVES

Transcranial direct current stimulation can be effective in reducing the craving for food, alcohol, and methamphetamine. Because its effects have not been tested on patients with opium use disorder, we investigated its efficacy when it is combined with a standard methadone maintenance therapy protocol.

METHODS

We carried out a pretest-posttest control group method to evaluate the effect of transcranial direct current stimulation at the dorsolateral prefrontal cortex (right anodal/left cathodal) on opium craving, depression, and anxiety symptoms. We considered opium craving as a primary outcome as well as depression and anxiety symptoms as secondary outcomes. Sixty participants with opium use disorder were randomly assigned into 3 groups (n = 20 for each group): (1) an active transcranial direct current stimulation with methadone maintenance treatment (active tDCS group), (2) sham transcranial direct current stimulation with methadone maintenance treatment (sham tDCS group), and (3) only methadone maintenance treatment (methadone maintenance treatment group). All participants completed the Desire for Drug Questionnaire, Obsessive-Compulsive Drug Use Scale, Beck Depression Inventory II, and Beck Anxiety Inventory a week before and a week after the treatment. The outcomes were assessed by independent assessors who were blind to the treatment conditions.

RESULTS

The active tDCS group had a significant reduction in opium craving, depression, and anxiety symptoms compared with the other 2 groups.

CONCLUSIONS

Our results provide a preliminary support for using the transcranial direct current stimulation along with methadone maintenance therapy in the treatment of patients with opium use disorder.

Mindfulness-Based Relapse Prevention and Transcranial Direct Current Stimulation to Reduce Heavy Drinking: A Double-Blind Sham-Controlled Randomized Trial

BACKGROUND

Mindfulness-based relapse prevention (MBRP) and transcranial direct current stimulation (tDCS) have independently shown benefits for treating alcohol use disorder (AUD). Recent work suggests tDCS may enhance mindfulness. The combination of MBRP and tDCS may provide synergistic benefits and may target both behavioral and neurobiological dysfunctions in AUD. The goal of this double-blind sham-controlled randomized trial was to examine the efficacy of a rolling group MBRP treatment combined with tDCS among individuals interested in reducing their drinking.

METHODS

Individuals who were interested in reducing their alcohol use (n = 84; 40.5% female; mean age = 52.3; 98.9% with current AUD) were randomized to receive active (2.0 milliamps) or sham (0.0 milliamps) anodal tDCS (5 cm × 3 cm electrode) of the right inferior frontal gyrus with the 5 cm × 3 cm cathodal electrode applied to the left upper arm, combined with 8 weeks of outpatient MBRP rolling group treatment. Assessments were conducted at baseline, posttreatment, and 2 months following treatment. The primary outcome was drinks per drinking day, and secondary outcomes were percent heavy drinking days, self-reported craving, alcohol cue reactivity in an alcohol cue task, and response inhibition in a stop signal reaction time task.

RESULTS

Results indicated significant reductions in drinks per drinking day over time, B(SE) = -0.535 (0.16), p = 0.001, and a significant dose effect for number of groups attended, B(SE) = -0.259 (0.11), p = 0.01. There were also significant effects of time and dose for number of groups attended on secondary outcomes of percent heavy drinking days and alcohol cue reactivity. There were no effects of active versus sham tDCS on primary or secondary outcomes.

CONCLUSIONS

Findings from the current study provide initial support for the effectiveness of rolling group MBRP as an outpatient treatment for drinking reduction. The current study did not find additive effects of this tDCS protocol in enhancing MBRP among individuals with drinking reduction goals.

Non-invasive brain stimulation in substance use disorders: implications for dissemination to clinical settings

With expanding knowledge of how neural circuitry is disrupted in substance use disorders (SUD), non-invasive brain stimulation (NIBS) techniques have emerged as potential strategies to directly modulate those neural circuits. There is some evidence supporting the two most common forms of NIBS, transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS), in the treatment of SUD. Yet results of recent studies have been mixed and critical methodological issues must be addressed before strong conclusions can be drawn. This review highlights recent evidence of NIBS for SUD, addressing the impact of stimulation on relevant clinical and cognitive outcomes in substance-using populations. Additionally, we aim to bring a clinical perspective to the opportunities and challenges of implementing neuromodulation in SUD treatment.

Polarity Specific Effects of Cross-Hemispheric tDCS Coupled With Approach-Avoidance Training on Chocolate Craving

Transcranial Direct Current Stimulation (tDCS) over the Dorsolateral Prefrontal Cortex (DLPFC) has already been shown to decrease craving for food. However, it remains unclear whether a single session of tDCS combined with a cognitive bias modification (CBM) task may affect explicit and implicit measures of craving for chocolate. Fifty-one healthy volunteers (38 females; mean age: 22.12 ± 3.38) were randomly allocated to CBM training based on the Approach Avoidance task and either Sham, Right anodal-Left cathodal (RALC), or Left anodal-Right cathodal (LARC) tDCS. Results show that there was an increase in the explicit craving for chocolate, as assessed by the Visual Analog Scale [F(2, 46) = 3.239, p = 0.048], from the baseline to post-intervention. Participants which received LARC tDCS were explicitly self-reporting more craving for chocolate than those that received RALC tDCS (p = 0.023). Moreover, this effect was also observed on the implicit measure [F(2, 46) = 4.168, p = 0.022]. LARC tDCS significantly increased the implicit preference for chocolate when comparing to both RALC (p = 0.009) and Sham tDCS (p = 0.034). Previous studies have shown that RALC tDCS over the PFC is able to effectively decrease craving for food. Interestingly, the present data not only does not reproduce such result, but instead it suggests that LARC tDCS can actually increase the preference for chocolate. This result is compatible with recent models of brain laterality, in which cue craving seems to be more dependent on the left hemisphere. Thus, shifting the activity to the left hemisphere (while simultaneously reducing the activity over the homotopic region) may have led to this increased implicit as well as explicit preference for chocolate.