Reward craving and withdrawal relief craving: assessment of different motivational pathways to alcohol intake

The Continuing Challenges of Studying Parallel Behaviours in Humans and Animal Models

The use of animal models continues to be essential for carrying out research into clinical phenomena, including addiction. However, the complexity of the clinical condition inevitably means that even the best animal models are inadequate, and this may go some way to account for the apparent failures of discoveries from animal models, including the identification of potential novel therapies, to translate to the clinic. We argue here that it is overambitious and misguided in the first place to attempt to model complex, multifacetted human disorders such as addiction in animals, and especially in rodents, and that all too frequently "validity" of such models is limited to superficial similarities, referred to as "face validity", that reflect quite different underlying phenomena and biological processes from the clinical situation. Instead, a more profitable approach is to identify (a) well-defined intermediate human behavioural phenotypes that reflect defined, limited aspects of, or contributors to, the human clinical disorder, and (b) to develop animal models that are homologous with those discrete human behavioural phenotypes in terms of psychological processes, and underlying neurobiological mechanisms. Examples of past and continuing weaknesses and suggestions for more limited approaches that may allow better homology between the test animal and human condition are made.

Does compulsion explain addiction?

One of the leading drug addiction theories states that habits and the underlying neural process of a ventral to dorsal striatal shift are the building blocks of compulsive drug-seeking behaviour and that compulsion is the maladaptive persistence of responding despite adverse consequences. Here we discuss that compulsive behaviour as defined primarily from the perspective of animal experimentation falls short of the clinical phenomena and their neurobiological correlates. Thus for the human condition, the concept of compulsive habbits should be critically addressed and potentially revised.

Longitudinal stability of reward and relief drinking phenotypes in community and treatment-seeking individuals who engage in heavy drinking

BACKGROUND

Precision medicine approaches aim to improve treatment outcomes by identifying which treatments work best for specific individual phenotypes. In the treatment of alcohol use disorder (AUD), precision medicine approaches have been proposed based on phenotypes characterized by individuals who drink primarily to enhance rewarding experiences (i.e., reward drinking) or those who drink primarily to relieve negative states (i.e., relief drinking). This study examined these phenotypes across treatment- and nontreatment-seeking individuals and the stability of the phenotypes over time.

METHODS

We used latent profile and latent transition analyses to identify and assess longitudinal stability (over 3 or 4 months) of reward and relief drinking subgroups within a nontreatment-seeking community sample that engaged in hazardous drinking (n = 189) and two treatment-seeking samples of individuals with AUD enrolled in two large clinical trials (n = 1726, n = 1383). We examined prospective associations with alcohol consumption and consequences at long-term follow-up (15 or 18 months).

RESULTS

Results supported four subgroups: low reward/low relief, low reward/high relief, high reward/low relief, and high reward/high relief. The community sample contained more individuals classified within the high reward/low relief subgroup than treatment-seeking samples. Subgroups were generally more stable over time in the community sample than in the treatment-seeking samples. Alcohol consumption and consequences decreased over time for the treatment-seeking samples, with consequences and drinking frequency decreasing for the community sample. Participants classified within the high reward/high relief and low reward/high relief groups reported the most consequences and consumption at long-term follow-up.

CONCLUSION

Reward and relief drinking phenotypes can be identified within community and treatment-seeking samples of individuals who drink heavily. The phenotypic subgroups appear to be stable over time in the absence of treatment, change somewhat during treatment, and provide utility in predicting alcohol consumption and consequences.

Neuroplasticity of the extended amygdala in opioid withdrawal and prolonged opioid abstinence

Opioid use disorder is characterized by excessive use of opioids, inability to control its use, a withdrawal syndrome upon discontinuation of opioids, and long-term likelihood of relapse. The behavioral stages of opioid addiction correspond with affective experiences that characterize the opponent process view of motivation. In this framework, active involvement is accompanied by positive affective experiences which gives rise to "reward craving," whereas the opponent process, abstinence, is associated with the negative affective experiences that produce "relief craving." Relief craving develops along with a hypersensitization to the negatively reinforcing aspects of withdrawal during abstinence from opioids. These negative affective experiences are hypothesized to stem from neuroadaptations to a network of affective processing called the "extended amygdala." This negative valence network includes the three core structures of the central nucleus of the amygdala (CeA), the bed nucleus of the stria terminalis (BNST), and the nucleus accumbens shell (NAc shell), in addition to major inputs from the basolateral amygdala (BLA). To better understand the major components of this system, we have reviewed their functions, inputs and outputs, along with the associated neural plasticity in animal models of opioid withdrawal. These models demonstrate the somatic, motivational, affective, and learning related models of opioid withdrawal and abstinence. Neuroadaptations in these stress and motivational systems are accompanied by negative affective and aversive experiences that commonly give rise to relapse. CeA neuroplasticity accounts for many of the aversive and fear-related effects of opioid withdrawal via glutamatergic plasticity and changes to corticotrophin-releasing factor (CRF)-containing neurons. Neuroadaptations in BNST pre-and post-synaptic GABA-containing neurons, as well as their noradrenergic modulation, may be responsible for a variety of aversive affective experiences and maladaptive behaviors. Opioid withdrawal yields a hypodopaminergic and amotivational state and results in neuroadaptive increases in excitability of the NAc shell, both of which are associated with increased vulnerability to relapse. Finally, BLA transmission to hippocampal and cortical regions impacts the perception of conditioned aversive effects of opioid withdrawal by higher executive systems. The prevention or reversal of these varied neuroadaptations in the extended amygdala during opioid withdrawal could lead to promising new interventions for this life-threatening condition.

Frontal EEG response to alcohol craving elicited by individually tailored video cues

BACKGROUND

Most findings on the pathophysiology of alcoholism are based on studies using resting-state electroencephalography (EEG). There are few studies on cue-induced craving and on its utility as an electrophysiological index. We examined quantitative EEG (qEEG) activities in alcoholics and social drinkers exposed to video cues and compared their association with subjective alcohol craving and other related psychiatric symptoms, including anxiety and depression.

METHODS

This is a between-subjects design. Adult male alcoholics (n = 34) and healthy social drinkers (n = 33) participated. In a laboratory, EEGs were recorded while the participants were presented with craving-inducing video stimuli. Measures used were the Visual Analog Scale (VAS) for subjective alcohol craving, Alcohol Urge Questionnaire (AUQ), Michigan Alcoholism Screening Test (MAST), Beck Anxiety Inventory (BAI), and Beck Depression Inventory (BDI) scores.

RESULTS

One-way analysis of covariance with age showed that alcoholics had significantly increased beta activity in the right DLPFC region (F4) (F = 4.029, p = 0.049), compared to social drinkers when craving-inducing stimuli were presented. Beta activity at the F4 electrode was positively correlated with AUQ (r = .284, p = 0.021), BAI (r = .398, p = 0.001), BDI (r = .291, p = 0.018), and changes in VAS (r = .292, p = 0.017) scores in both alcoholics and social drinkers. In alcoholics, beta activity was significantly correlated with BAI (r = .392, p = 0.024).

CONCLUSIONS

These findings imply functional importance of hyperarousal and negative emotions upon exposure to craving-inducing cues. Frontal EEG indices with beta power could serve as an objective electrophysiological index of craving induced by individually tailored video cues in alcohol consumption behavior.

Theoretical Frameworks and Mechanistic Aspects of Alcohol Addiction: Alcohol Addiction as a Reward Deficit/Stress Surfeit Disorder

Alcohol use disorder (AUD) can be defined by a compulsion to seek and take alcohol, the loss of control in limiting intake, and the emergence of a negative emotional state when access to alcohol is prevented. Alcohol use disorder impacts multiple motivational mechanisms and can be conceptualized as a disorder that includes a progression from impulsivity (positive reinforcement) to compulsivity (negative reinforcement). Compulsive drug seeking that is associated with AUD can be derived from multiple neuroadaptations, but the thesis argued herein is that a key component involves the construct of negative reinforcement. Negative reinforcement is defined as drug taking that alleviates a negative emotional state. The negative emotional state that drives such negative reinforcement is hypothesized to derive from the dysregulation of specific neurochemical elements that are involved in reward and stress within basal forebrain structures that involve the ventral striatum and extended amygdala, respectively. Specific neurochemical elements in these structures include decreases in reward neurotransmission (e.g., decreases in dopamine and opioid peptide function in the ventral striatum) and the recruitment of brain stress systems (e.g., corticotropin-releasing factor [CRF]) in the extended amygdala, which contributes to hyperkatifeia and greater alcohol intake that is associated with dependence. Glucocorticoids and mineralocorticoids may play a role in sensitizing the extended amygdala CRF system. Other components of brain stress systems in the extended amygdala that may contribute to the negative motivational state of withdrawal include norepinephrine in the bed nucleus of the stria terminalis, dynorphin in the nucleus accumbens, hypocretin and vasopressin in the central nucleus of the amygdala, and neuroimmune modulation. Decreases in the activity of neuropeptide Y, nociception, endocannabinoids, and oxytocin in the extended amygdala may also contribute to hyperkatifeia that is associated with alcohol withdrawal. Such dysregulation of emotional processing may also significantly contribute to pain that is associated with alcohol withdrawal and negative urgency (i.e., impulsivity that is associated with hyperkatifeia during hyperkatifeia). Thus, an overactive brain stress response system is hypothesized to be activated by acute excessive drug intake, to be sensitized during repeated withdrawal, to persist into protracted abstinence, and to contribute to the compulsivity of AUD. The combination of the loss of reward function and recruitment of brain stress systems provides a powerful neurochemical basis for a negative emotional state that is responsible for the negative reinforcement that at least partially drives the compulsivity of AUD.

Right inferior frontal gyrus theta-burst stimulation reduces smoking behaviors and strengthens fronto-striatal-limbic resting-state functional connectivity: a randomized crossover trial

Introduction

Functional and anatomical irregularities in the right inferior frontal gyrus (rIFG), a ventrolateral prefrontal region that mediates top-down inhibitory control over prepotent behavioral responding, are implicated in the ongoing maintenance of nicotine dependence (ND). However, there is little research on the effects of neuromodulation of the rIFG on smoking behavior, inhibitory control, and resting-state functional connectivity (rsFC) among individuals with ND.

Methods

In this double-blind, crossover, theta-burst stimulation (TBS) study, adults with ND (N = 31; female: n = 15) completed a baseline session and were then randomized to two counterbalanced sessions of functionally neuronavigated TBS to the rIFG: continuous TBS (cTBS) on 1 day and intermittent TBS (iTBS) on another. Differences in cigarette cravings, smoking, and fronto-striatal-limbic rsFC were assessed.

Results

Relative to baseline, cTBS significantly reduced appetitive and withdrawal cravings immediately after treatment. The effects of cTBS on withdrawal craving persisted for 24 h, as well as produced a reduction in smoking. Furthermore, cTBS significantly strengthened rsFC between the rIFG pars opercularis and subcallosal cingulate (fronto-striatal circuit), and between the rIFG pars opercularis and the right posterior parahippocampal gyrus (fronto-limbic circuit). At post-24 h, cTBS-induced increase in fronto-striatal rsFC was significantly associated with less appetitive craving, while the increase in fronto-limbic rsFC was significantly associated with less withdrawal craving and smoking.

Discussion

These findings warrant further investigation into the potential value of rIFG cTBS to attenuate smoking behavior among individuals with ND.

The Association of Non-Drug-Related Pavlovian-to-Instrumental Transfer Effect in Nucleus Accumbens With Relapse in Alcohol Dependence: A Replication

BACKGROUND

The Pavlovian-to-instrumental transfer (PIT) paradigm measures the effects of Pavlovian conditioned cues on instrumental behavior in the laboratory. A previous study conducted by our research group observed activity in the left nucleus accumbens (NAcc) elicited by a non-drug-related PIT task across patients with alcohol dependence (AD) and healthy control subjects, and the left NAcc PIT effect differentiated patients who subsequently relapsed from those who remained abstinent. In this study, we aimed to examine whether such effects were present in a larger sample collected at a later date.

METHODS

A total of 129 recently detoxified patients with AD (21 females) and 74 healthy, age- and gender-matched control subjects (12 females) performing a PIT task during functional magnetic resonance imaging were examined. After task assessments, patients were followed for 6 months. Forty-seven patients relapsed and 37 remained abstinent.

RESULTS

We found a significant behavioral non-drug-related PIT effect and PIT-related activity in the NAcc across all participants. Moreover, subsequent relapsers showed stronger behavioral and left NAcc PIT effects than abstainers. These findings are consistent with our previous findings.

CONCLUSIONS

Behavioral non-drug-related PIT and neural PIT correlates are associated with prospective relapse risk in AD. This study replicated previous findings and provides evidence for the clinical relevance of PIT mechanisms to treatment outcome in AD. The observed difference between prospective relapsers and abstainers in the NAcc PIT effect in our study is small overall. Future studies are needed to further elucidate the mechanisms and the possible modulators of neural PIT in relapse in AD.

The Dopamine System in Mediating Alcohol Effects in Humans

Brain-imaging studies show that the development and maintenance of alcohol use disorder (AUD) is determined by a complex interaction of different neurotransmitter systems and multiple psychological factors. In this context, the dopaminergic reinforcement system appears to be of fundamental importance. We focus on the excitatory and depressant effects of acute versus chronic alcohol intake and its impact on dopaminergic neurotransmission. Furthermore, we describe alterations in dopaminergic neurotransmission as associated with symptoms of alcohol dependence. We specifically focus on neuroadaptations to chronic alcohol consumption and their effect on central processing of alcohol-associated and reward-related stimuli. Altered reward processing, complex conditioning processes, impaired reinforcement learning, and increased salience attribution to alcohol-associated stimuli enable alcohol cues to drive alcohol seeking and consumption. Finally, we will discuss how the neurobiological and neurochemical mechanisms of alcohol-associated alterations in reward processing and learning can interact with stress, cognition, and emotion processing.

Attentional biases and daily game craving dynamics: An ecological momentary assessment study

BACKGROUND AND AIMS

Theories posit that the combination of external (e.g. cue exposure) and internal (e.g. attention biases) factors contributes to the development of game craving. Nevertheless, whether different components of attentional biases (namely, engagement bias and disengagement bias) play separate roles on game craving has not been fully elucidated. We aimed to examine the associations between two facets of attentional biases and game craving dynamics under a daily life setting.

METHODS

Participants (110 regular internet game players) accomplished the modified attentional assessment task in the laboratory, after which they entered a 10-day ecological momentary assessment (EMA) to collect data on their momentary game craving and occurrence of game-related events at five different time points per day.

RESULTS

We found that occurrence of game-related events was significantly associated with increased game craving. Moreover, attentional disengagement bias, instead of engagement bias, bore on the occasional level variations of game craving as moderating variables. Specifically, attentional disengagement bias, not engagement bias, was associated with a greater increase in game craving immediately after encountering a game-related event; however, neither attentional engagement bias nor disengagement bias was associated with the craving maintenance after a relatively long period.

DISCUSSION AND CONCLUSIONS

The present study highlights the specific attentional processes involved in game craving dynamics, which could be crucial for designing interventions for attentional bias modification (ABM) in Internet Gaming Disorder (IGD) populations.

The Role of Impulsivity and Reward Deficiency in "Liking" and "Wanting" of Potentially Problematic Behaviors and Substance Uses

A few studies have examined the changes in substance- and behavior-related "wanting" and "liking" of human subjects, the key properties of Incentive Sensitization Theory (IST). The aim of this study was to examine the dissociation between "wanting" and "liking" as a function of usage frequency, intensity, and subjective severity in individuals across four substances (alcohol, nicotine, cannabis, and other drugs) and ten behaviors (gambling, overeating, gaming, pornography use, sex, social media use, Internet use, TV-series watching, shopping, and work). Also, the potential roles of impulsivity and reward deficiency were investigated in "wanting," "liking," and wellbeing. The sex differences between "wanting" and "liking" were also examined. Based on our findings using structural equation modeling with 749 participants (503 women, M age = 35.7 years, SD = 11.84), who completed self-report questionnaires, "wanting" increased with the severity, frequency, and intensity of potentially problematic use, while "liking" did not change. Impulsivity positively predicted "wanting," and "wanting" positively predicted problem uses/behaviors. Reward deficiency positively predicted problem uses/behaviors, and both impulsivity and problem uses/behaviors negatively predicted wellbeing. Finally, women showed higher levels of "wanting," compared to men. These findings demonstrate the potential roles of incentive sensitization in both potentially problematic substance uses and behaviors.

An Overview of Glycine Transporter Subtype 1 Inhibitors Under Preclinical and Clinical Evaluation for the Treatment of Alcohol Abuse

Abstract:

Being a historical issue that withstands multiple societal control measures, alcohol abuse remains a major healthcare problem. Despite worldwide efforts to limit consumption and educate people about its effects, consumption rates remain unchanged. Alcohol abuse arises from chronic alcohol exposure-caused permanent synaptic plasticity changes in the brain. These manifest in life-threatening withdrawal symptoms and drive relapse even after detoxification and treatment. Since ethanol has multiple targets in the human brain, it warrants a multiapproach therapy; here we introduce the potential therapeutic effects of glycine transporter subtype 1 inhibitors. We have listed the various glycine transporter 1 inhibitors used in studies of alcoholism and how they influenced glycine release from rat hippocampus was demonstrated in a preliminary study. Glycine transporters modulate both glutamatergic and glycinergic pathways: (i) glutamatergic neurotransmission plays an important role in the development of chronic changes in alcoholism as daily alcohol administration was shown to increase N-methyl-D-aspartic acid receptor activity long-term, and (ii) ethanol has access to the dopaminergic reward system via glycine receptors, being an allosteric modulator of glycine receptors. This manuscript summarises the progress and development of glycine transporter 1 inhibitors, characterizing them by their mode of action, adverse effects, and discusses their clinical applicability. Furthermore, we highlight the progress in the latest clinical trials, outline currently applied treatment methods, and offer suggestions for implementing glycine transporter 1 inhibitors into the long-term treatment of alcohol abuse.

Computational analysis of probabilistic reversal learning deficits in male subjects with alcohol use disorder

BACKGROUND

Alcohol use disorder is characterized by perseverative alcohol use despite negative consequences. This hallmark feature of addiction potentially relates to impairments in behavioral flexibility, which can be measured by probabilistic reversal learning (PRL) paradigms. We here aimed to examine the cognitive mechanisms underlying impaired PRL task performance in patients with alcohol use disorder (AUDP) using computational models of reinforcement learning.

METHODS

Twenty-eight early abstinent AUDP and 27 healthy controls (HC) performed an extensive PRL paradigm. We compared conventional behavioral variables of choices (perseveration; correct responses) between groups. Moreover, we fitted Bayesian computational models to the task data to compare differences in latent cognitive variables including reward and punishment learning and choice consistency between groups.

RESULTS

AUDP and HC did not significantly differ with regard to direct perseveration rates after reversals. However, AUDP made overall less correct responses and specifically showed decreased win-stay behavior compared to HC. Interestingly, AUDP showed premature switching after no or little negative feedback but elevated proneness to stay when accumulation of negative feedback would make switching a more optimal option. Computational modeling revealed that AUDP compared to HC showed enhanced learning from punishment, a tendency to learn less from positive feedback and lower choice consistency.

CONCLUSION

Our data do not support the assumption that AUDP are characterized by increased perseveration behavior. Instead our findings provide evidence that enhanced negative reinforcement and decreased non-drug-related reward learning as well as diminished choice consistency underlie dysfunctional choice behavior in AUDP.

Clinical Outcomes of Severe Forms of Early Social Stress

Early social stress, particularly severe but nevertheless frequent forms such as abuse and neglect, are among the major risk factors for the development of mental disorders. However, we only have very limited knowledge of the psychobiological disease mechanisms underlying the influence of early life stress and stress-related disorders during this vulnerable phase of life. Early stress can have long-lasting adverse effects on the brain and other somatic systems, e.g. through influences on brain development. In adulthood, the prior experience of abuse or neglect can result in complex clinical profiles. Besides conditions such as mood and anxiety disorders as well as posttraumatic stress disorder, substance use disorders (SUD) are among the most prevalent sequelae of early social stress. Current social stress further influences the development and maintenance of these disorders, e.g., by increasing the risk of relapses. In this chapter, we will first give an overview of currently used methods to assess the phenomenology and pathophysiology of stress-related disorders and then focus on the phenomenological and neurobiological background of the interaction between early social stress and SUD. We will give an overview of important insights from neuroimaging studies and will also highlight recent findings from studies using digital tools such as ecological momentary assessment or virtual reality to capture the influence of early social stress as well as current social stress in everyday life of persons with SUD.

Reward drinking and naltrexone treatment response among young adult heavy drinkers

AIMS

Theory-driven, exploratory study to: (i) identify a reward drinking phenotype in young adults; (ii) evaluate this phenotype as a predictor of naltrexone response; and (iii) examine mechanisms of naltrexone in reward drinkers.

DESIGN

Secondary analysis of a randomized controlled trial.

SETTING

USA.

PARTICIPANTS

A total of 128 young adult (ages 18-25) heavy drinkers.

INTERVENTIONS

Naltrexone versus placebo.

MEASUREMENTS

Daily surveys assessed affect, urge, drinking, and context. The Drinking Motives Questionnaire was used to identify phenotypes based on reward (enhancement motives) and relief (coping motives) drinking.

FINDINGS

We identified three profiles: "Low reward/Low relief" (14.1%; low enhancement/low coping motives); "Reward drinkers" (62.2%; high enhancement/low coping motives); and "High reward/High relief" (22.7%; high enhancement/high coping motives). Among reward drinkers (versus low profile), naltrexone significantly reduced percent days drinking to intoxication (blood alcohol concentration [BAC] ≥0.08) (PDI) (d = 0.56; 95% CI [0.17, 0.96]) and percent high intensity drinking days (PHID) (8/10 drinks for women/men) (d = 0.32; 95% CI [0.01, 0.68]). Among the high reward/high relief profile drinkers (versus low profile), naltrexone reduced PHID (d = 0.69; 95% CI [0.02, 1.50]). Using profile-informed cutoffs and observed scores (for clinical applicability): (i) among cutoff-derived reward drinkers, we found a medium-to-large (d = 0.66; 95% CI [0.24, 1.16]) and small effect (d = 0.28; 95% CI [0.04, 0.72]) of naltrexone in reducing PDI and PHID, respectively; and (ii) among the cutoff-derived high reward/high relief subgroup, we found a medium-to-large effect (d = 0.63; 95% CI [0.05, 1.1]) of naltrexone in reducing PHID. Among reward drinkers (not other profiles), naltrexone reduced drinking on days a drinking event occurred by weakening the within-day association between positive affect and urges (P < 0.05).

CONCLUSIONS

Naltrexone has pronounced effects in reducing risky drinking among young adult reward drinkers (high reward/low relief) by reducing urges on days when individuals have higher positive affect and are exposed to a drinking event. Naltrexone also appears to reduce risky drinking among young adult high reward/high relief drinkers, but not via the same mechanism.

FMRI-based prediction of naltrexone response in alcohol use disorder: a replication study

Pharmacological treatment in alcohol use disorder suffers from modest effect sizes. Efforts have been undertaken to identify patient characteristics that help to select individuals that benefit from pharmacological treatment. Previous studies indicated that neural alcohol cue-reactivity (CR) might provide a marker that identifies patients, which benefit from naltrexone treatment.We investigated the reproducibility of the association between ventral striatum (VS) activation and naltrexone (NTX) treatment response by analyzing data from a recent longitudinal clinical trial in N = 44 abstinent treatment-seeking alcohol-dependent patients. A follow-up was conducted over 3 months. We computed the percentage of significant voxels in VS and tested main effects and interactions with NTX treatment on relapse risk using Cox Regression models.We found a significant interaction effect between pre-treatment cue reactivity in the VS and NTX treatment on time to first heavy relapse (Hazard Ratio = 7.406, 95% CI 1.17-46.56, p = 0.033), such that the patient group with high VS activation (defined by a mean split) showed a significant medication effect (Hazard Ratio = 0.140, 95% CI 0.02-0.75, p = 0.022) with a number needed to treat of 3.4 [95% CI 2.413.5], while there was no significant effect in the group with low VS activation (Hazard Ratio = 0.726, p = 0.454).Thus, using an independent sample we replicated the previously described positive association between VS activation and NTX efficacy. Although our results should be considered cautiously in light of the small sample size, our results support the potential of neural alcohol CR as a tool for precision medicine approaches in alcohol dependence.

Reinforcement-based cognitive biases as vulnerability factors in alcohol addiction: From humans to animal models

Alcohol use disorder (AUD) is one of the most common, but still poorly treated, psychiatric conditions. Developing new treatments requires a better understanding of the aetiology of symptoms and evaluation of novel therapeutic targets in preclinical studies. Recent developments in our understanding of the reinforcement-based cognitive biases (RBCBs) that contribute to the development of AUD and its treatment offer new opportunities for both clinical and preclinical research. In this review, we first briefly describe psychological and cognitive theories that involve various aspects of reinforcement sensitivity in the development, maintenance, and recurrence of alcohol addiction. Furthermore, in separate sections, we describe studies investigating RBCBs and their neural, neurochemical, and pharmacological correlates, and we discuss possible interactions between RBCBs and trajectories of AUD. Finally, we describe how recent translational studies using state-of-the-art animal models can facilitate our understanding of the role of reinforcement sensitivity and RBCBs in various aspects of AUD.

Ambulatory assessment for precision psychiatry: Foundations, current developments and future avenues

Precision psychiatry stands to benefit from the latest digital technologies for assessment and analyses to tailor treatment towards individuals. Insights into dynamic psychological processes as they unfold in humans' everyday life can critically add value in understanding symptomatology and environmental stressors to provide individualized treatment where and when needed. Towards this goal, ambulatory assessment encompasses methodological approaches to investigate behavioral, physiological, and biological processes in humans' everyday life. It combines repeated assessments of symptomatology over time, e.g., via Ecological Momentary Assessment (e.g., smartphone-diaries), with monitoring of physical behavior, environmental characteristics (such as geolocations, social interactions) and physiological function via sensors, e.g., mobile accelerometers, global-positioning-systems, and electrocardiography. In this review, we expand on promises of ambulatory assessment in the investigation of mental states (e.g., real-life, dynamical and contextual perspective), on chances for precision psychiatry such as the prediction of courses of psychiatric disorders, detection of tipping points and critical windows of relapse, and treatment effects as exemplified by ongoing projects, and on future avenues of how ambulatory interventions can benefit personalized care for psychiatric patients (e.g., through real-time feedback in everyday life). Ambulatory assessment is a key contributor to precision psychiatry, opening up promising avenues in research, diagnoses, prevention and treatment.

Mindfulness in Treatment Approaches for Addiction — Underlying Mechanisms and Future Directions

Purpose of Review

While the treatment of addictive disorders proves to be challenging, new treatment approaches that evolved around the concepts of mindfulness and acceptance have been utilized and investigated in recent years. Our goal is to summarize the efficacy and possible underlying mechanisms of mindfulness-based interventions (MBI) in addictive disorders.

Recent Findings

Various meta-analyses have suggested that MBIs show clinical efficacy in the treatment of addictive disorders. Considering the factors that impact addictive disorders, MBIs have been indicated to augment responsiveness to natural rewards in contrast to addiction-related cues as well as to increase top-down cognitive control, decrease subjective and physiological stress perception, and enhance positive affect.

Summary

In summary, MBIs hold promise in treating addictive disorders while larger randomized controlled trials with longitudinal study designs are needed to confirm their utility. Newest clinical endeavors strive to enhance the clinical utility of MBIs by augmentation or personalization.

Opioid-induced structural and functional plasticity of medium-spiny neurons in the nucleus accumbens

Opioid Use Disorder (OUD) is a chronic relapsing clinical condition with tremendous morbidity and mortality that frequently persists, despite treatment, due to an individual's underlying psychological, neurobiological, and genetic vulnerabilities. Evidence suggests that these vulnerabilities may have neurochemical, cellular, and molecular bases. Key neuroplastic events within the mesocorticolimbic system that emerge through chronic exposure to opioids may have a determinative influence on behavioral symptoms associated with OUD. In particular, structural and functional alterations in the dendritic spines of medium spiny neurons (MSNs) within the nucleus accumbens (NAc) and its dopaminergic projections from the ventral tegmental area (VTA) are believed to facilitate these behavioral sequelae. Additionally, glutamatergic neurons from the prefrontal cortex, the basolateral amygdala, the hippocampus, and the thalamus project to these same MSNs, providing an enriched target for synaptic plasticity. Here, we review literature related to neuroadaptations in NAc MSNs from dopaminergic and glutamatergic pathways in OUD. We also describe new findings related to transcriptional, epigenetic, and molecular mechanisms in MSN plasticity in the different stages of OUD.

Association between polymorphism in gene related to the dopamine circuit and motivations for drinking in patients with alcohol use disorder

The development of alcohol use disorder (AUD) is influenced by genetic, psychological, and social factors. However, the identification of the load of each of these factors and the association between them is still debatable. This study aimed to explore the load of the association between AUD and polymorphisms in genes of the dopaminergic system, as well as with drinking triggers. The study comprised 227 inpatients with AUD and 174 controls. The pattern and motivations for drinking were evaluated using the Alcohol Use Disorders Identification Test (AUDIT) and the Inventory of Drinking Situations (IDS). Analyses of genetic variation in genes encoding dopaminergic were performed using next generation sequencing. We observed an significant association between a polymorphism in DDC (rs11575457) and AUD. Positive reinforcement factors as urges/temptations to drink and pleasant emotion, in isolation, were the significantly related elements to drinking. In addition, negative (physical discomfort) and positive reinforcement factors (testing personal control; pleasant time with others) significantly reinforced the interaction with DDC genetic variant for increased odds of an individual presenting AUD. These results indicated a complex relationship between the dopaminergic system and the drug-seeking behavior profiles.

Effects of couple conflict on alcohol craving: Does intimate partner violence play a role?

OBJECTIVE

Social stress in the form of maladaptive relationship conflict is a common precipitant to alcohol misuse and problems. Research has also established a clear causal association between alcohol misuse and relationship conflict in the form of intimate partner violence (IPV). Despite the robust literature linking relationship conflict and problematic drinking using survey methodology, no laboratory studies have examined the proximal association between relationship conflict and alcohol craving among couples, or the influence of IPV perpetration and victimization on this association.

METHOD

As part of a larger randomized controlled trial, 30 different-sex community couples with substance misuse completed a laboratory conflict resolution task. Participants reported subjective alcohol craving on a Likert-type scale immediately, before, and after the task. Conflict behaviors were coded by trained observers. Analyses were conducted using a multilevel modeling framework to account for the dyadic nature of the data.

RESULTS

Findings indicate that psychological and physical IPV perpetration and victimization strengthened the associations between negative and positive conflict behaviors and alcohol craving among men only. Contrary to our hypotheses, no main or moderating effects of conflict behaviors, IPV perpetration, or IPV victimization were found for women.

CONCLUSIONS

Findings from this exploratory study suggest that in this sample, relationship conflict and IPV in one's current relationship played a more impactful role on acute alcohol craving among men compared to women. Future studies should examine the role of specific conflict behaviors on alcohol craving and relapse risk, and patterns of communication that might increase or reduce risk for exacerbated alcohol craving.

A meta-analysis of craving studies in schizophrenia spectrum disorders

OBJECTIVE

DSM-5 Substance Use Disorders (SUD) are frequent and debilitating comorbidities displayed by patients with schizophrenia spectrum disorders (SZ). One crucial feature of SUD is drug craving, an intense desire to consume a substance, commonly divided into reward and relief dimensions. Here, we conducted a meta-analysis of studies investigating craving in individuals with both SUD and SZ in order to examine whether these patients exhibit a distinct pattern of craving as compared to patients with SUD without SZ.

METHOD

Meta-analysis based on the PRISMA guidelines.

RESULTS

Sixteen relevant publications were identified by a systematic search of databases, which included 1219 individuals (589 SUD-SZ and 630 SUD-without-SZ). Of the 16 studies, 11 focused on tobacco, 3 on cannabis and 2 on cocaine. When considered across all studies, SUD-SZ had significantly higher scores than SUD-without-SZ for global craving with medium effect size (k_{number of studies} = 16, Zr = 0.20 [0.15, 0.26], equivalent d = 0.41, P < 0.001). Discrete patterns emerged for reward (k = 7, Zr = 0.10 [0.02, 0.17], equivalent d = 0.20, P < 0.05) and relief (k = 7, Zr = 0.25 [0.17, 0.33], d = 0.52, P < 0.001) craving, and the direct comparison revealed a significantly greater effect for relief than reward (χ²(1) = 7.40 P = 0.007).

CONCLUSION

These results suggest that SUD-SZ cases experience higher craving, more specifically for relief, in comparison to patients with SUD-without-SZ. These clinical findings can foster the development of tailored addiction therapies for this specific comorbid population.

Brain functional connectivity in chronic tic disorders and Gilles de la Tourette syndrome

The pathophysiology of chronic tic disorder (cTD) and Gilles de la Tourette syndrome (GTS) is characterized by the dysfunction of both motor and non - motor cortico - striatal - thalamo - cortical (CSTC) circuitries, which leads to tic release and comorbids. A role of fronto - parietal network (FPN) connectivity breakdown has been postulated for tic pathogenesis, given that the FPN entertain connections with limbic, paralimbic, and CSTC networks. Our study was aimed at characterizing the FPN functional connectivity in cTD and GTS in order to assess the role of its deterioration in tic severity and the degree of comorbids. We recorded scalp EEG during resting state in patients with cTD and GTS. The eLORETA current source densities were analyzed, and the lagged phase synchronization (LPS) was calculated to estimate nonlinear functional connectivity between cortical areas. We found that the FPN functional connectivity in delta band was more detrimental in more severe GTS patients. Also, the sensorimotor functional connectivity in beta2 band was stronger in more severe cTD and GTS patients. FPN functional connectivity deterioration correlated with comorbids presence and severity in patients with GTS. Our data suggest that a FPN disconnection may contribute to the motoric symptomatology and comorbid severity in GTS, whereas sensorimotor disconnection may contribute to tic severity in cTD and GTS. Although preliminary, our study points out a differently disturbed brain connectivity between patients with cTD and GTS. This may serve as diagnostic marker and potentially interesting base to develop pharmacological and noninvasive neuromodulation trials aimed at reducing tic symptomatology.

Anterior Cingulate Cortex Implants for Alcohol Addiction: A Feasibility Study

Abnormal neural activity, particularly in the rostrodorsal anterior cingulate cortex (rdACC), appears to be responsible for intense alcohol craving. Neuromodulation of the rdACC using cortical implants may be an option for individuals with treatment-resistant alcohol dependence. This study assessed the effectiveness and feasibility of suppressing alcohol craving using cortical implants of the rdACC using a controlled one-group pre- and post-test study design. Eight intractable alcohol-dependent participants (four males and four females) were implanted with two Lamitrode 44 electrodes over the rdACC bilaterally connected to an internal pulse generator (IPG). The primary endpoint, self-reported alcohol craving reduced by 60.7% (p = 0.004) post- compared to pre-stimulation. Adverse events occurred in four out of the eight participants. Electrophysiology findings showed that among responders, there was a post-stimulation decrease (p = 0.026) in current density at the rdACC for beta 1 band (13-18 Hz). Results suggest that rdACC stimulation using implanted electrodes may potentially be a feasible method for supressing alcohol craving in individuals with severe alcohol use disorder. However, to further establish safety and efficacy, larger controlled clinical trials are needed.

[Effect of clinical characteristics on relapse of alcohol dependence: a prospective cohort study]

OBJECTIVE

To investigate whether craving and demographic factors to predict relapse in alcohol dependence.

METHODS

This study was a prospective cohort study. From August 2017 to August 2018, 158 Han male inpatients who met the diagnositic and statistical manual disorders-fourth version(DSM-IV) alcohol dependence diagnostic criteria were recruited from three mental hospitals in China. The participants were interviewed at baseline and followed up by telephone after 3 months for assessment. The baseline assessment after the acute withdrawal period included demographic data and alcohol-related data, clinical institute withdrawal assessment-advanced revised (CIWA-Ar), withdrawal and cue-induced craving on visual analog scale (VAS), Michigan alcoholism screening test (MAST), self-rating anxiety scale (SAS), self-rating depression scale (SDS) and alcohol urge questionnaire (AUQ). According to the follow-up results, "relapse" was defined as the consumption of beverages containing ethanol at any time during the follow-up study, and "time to relapse" was defined as the number of days from the first drinking to the baseline. Whether relapse occurred and the time to relapse were the primary endpoints. Cox proportional hazard regression model was used to analyze the factors affecting the relapse of alcohol dependence.

RESULTS

In the study, 158 alcohol dependence patients were finally included, age from 21 to 60 years, with the mean age of (40.31±9.14) years. The relapse rate was 63.7% three months after baseline assessment. According to Cox univariate analysis and multivariate analysis, the age (OR=0.975, P=0.030) and CIWA-Ar scores (OR=1.126, P=0.010) significantly predicted relapse. And there was no significant difference in education level, marital status, withdrawal and cue-induced craving on VAS, SAS and SDS between the relapse group and the non-relapse group (P>0.05).

CONCLUSION

Age and severity of alcohol-dependent withdrawal symptoms during hospitalization are significantly related to relapse for alcohol in alcohol-dependent patients. To be exact, the older age is a protective factor, that is to say, the younger patients are prone to relapse, while the risk of relapse is raised by the higher severity of withdrawal symptoms. However, neither cue-induced nor withdrawal craving can predict relapse of alcohol-dependent patients.

Affective startle modulation and psychopathology: Implications for appetitive and defensive brain systems

Startle reflex potentiation versus startle attenuation to unpleasant versus pleasant stimuli likely reflect priming of the defensive versus appetitive motivational systems, respectively. This review summarizes and systemizes the literature on affective startle modulation related to psychopathologies with the aim to reveal underlying mechanisms across psychopathologies. We found evidence for psychopathologies characterized by increased startle potentiation to unpleasant stimuli (anxiety disorders), decreased startle potentiation to unpleasant stimuli (psychopathy), decreased startle attenuation to pleasant stimuli (ADHD), as well as a general hyporeactivity to affective stimuli (depression). Increased versus decreased startle responses to disorder-specific stimuli characterize specific phobia and drug dependence. No psychopathology is characterized by increased startle attenuation to standard pleasant stimuli or a general hyperreactivity to affective stimuli. This review indicates that the defensive and the appetitive systems operate independently mostly in accordance with the motivational priming hypothesis and that affective startle modulation is a highly valuable paradigm to unraveling dysfunctions of the defensive and appetitive systems in psychopathologies as requested by the Research Domain Criteria initiative.

Neural correlates of instrumental responding in the context of alcohol-related cues index disorder severity and relapse risk

The influence of Pavlovian conditioned stimuli on ongoing behavior may contribute to explaining how alcohol cues stimulate drug seeking and intake. Using a Pavlovian-instrumental transfer task, we investigated the effects of alcohol-related cues on approach behavior (i.e., instrumental response behavior) and its neural correlates, and related both to the relapse after detoxification in alcohol-dependent patients. Thirty-one recently detoxified alcohol-dependent patients and 24 healthy controls underwent instrumental training, where approach or non-approach towards initially neutral stimuli was reinforced by monetary incentives. Approach behavior was tested during extinction with either alcohol-related or neutral stimuli (as Pavlovian cues) presented in the background during functional magnetic resonance imaging (fMRI). Patients were subsequently followed up for 6 months. We observed that alcohol-related background stimuli inhibited the approach behavior in detoxified alcohol-dependent patients (t = - 3.86, p < .001), but not in healthy controls (t = - 0.92, p = .36). This behavioral inhibition was associated with neural activation in the nucleus accumbens (NAcc) (t₍₃₀₎ = 2.06, p < .05). Interestingly, both the effects were only present in subsequent abstainers, but not relapsers and in those with mild but not severe dependence. Our data show that alcohol-related cues can acquire inhibitory behavioral features typical of aversive stimuli despite being accompanied by a stronger NAcc activation, suggesting salience attribution. The fact that these findings are restricted to abstinence and milder illness suggests that they may be potential resilience factors.Clinical trial: LeAD study, http://www.lead-studie.de , NCT01679145.

An experimental examination of cognitive processes and response inhibition in patients seeking treatment for buying-shopping disorder

There is an ongoing debate about whether buying-shopping disorder (BSD) should be acknowledged as a behavioral addiction. The current study investigated if mechanisms that play a prominent role in disorders due to substance use or addictive behaviors are relevant in BSD, particularly cue reactivity, craving, cognitive bias and reduced inhibitory control regarding addiction-relevant cues. The study included 39 treatment-seeking patients with BSD and 39 healthy control (HC) participants (29 women and 10 men in each group). Subjective responses toward buying/shopping-relevant visual cues were compared in patients vs. control participants. Experimental paradigms with neutral and semi-individualized buying/shopping-related pictures were administered to assess attentional bias, implicit associations and response inhibition with respect to different visual cues: Dot-probe paradigm (DPP), Implicit Association Task (IAT), Go/nogo-task (GNG). The severity of BSD, craving for buying/shopping, and symptoms of comorbid mental disorders (anxiety, depressive and hoarding disorders) were measured using standardized questionnaires. The BSD-group showed more general craving for buying/shopping, stronger subjective craving reactions towards buying/shopping-related visual cues, and more symptoms of anxiety, depression and hoarding disorder than control participants. Task performance in the DPP, IAT and GNG paradigm did not differ between the two groups. The present findings confirm previous research concerning the crucial role of craving in BSD. The assumption that attentional bias, implicit associations and deficient inhibitory control with respect to buying/shopping-related cues are relevant in BSD could not be proven. Future research should address methodological shortcomings and investigate the impact of acute psychosocial stress and present mood on craving responses, cognitive processing, and response inhibition in patients with BSD.

Identifying Triggers of Alcohol Craving to Develop Effective Virtual Environments for Cue Exposure Therapy

Background: Many studies have indicated that alcohol craving is a core mechanism in the acquisition, maintenance, and precipitation of relapse in alcohol use disorder (AUD). A common treatment approach in AUD is cue exposure therapy (CET). New technologies like virtual reality (VR) have the potential to enhance the effectiveness of CET by creating realistic scenarios in naturalistic environments. In this study, we aimed to determine relevant triggers of alcohol craving in patients with AUD.

Methods: We enrolled 75 outpatients diagnosed with AUD according to the DSM-5 criteria Participants completed the Alcohol Use Disorder Identification Test and a self-administered questionnaire to assess alcohol craving. The variables included in the craving questionnaire were as follows: presence of others, situations, time of the day, day of the week, mood, and type of alcoholic beverage.

Results: Greater levels of alcohol craving were seen in many situations, including being at a party, in a restaurant, in a bar or pub, and at home. Drinking alone and drinking with two or more friends were equally associated with higher levels of craving. Drinking at night and drinking at weekends also emerged as triggers for alcohol craving. Emotional states like anxiety or tension, sadness, stress, frustration, or irritability were highly associated with urges to drink alcohol. The alcoholic drinks most highly associated with increased levels of craving were beer, wine, and whisky. Gender and age implications were discussed.

Conclusion: This study is part of a larger project aiming to develop and validate CET based on VR technology for patients with AUD who are resistant to classical treatment. The identified triggers have been used to develop relevant VR environments for CET, and further research is ongoing to implement our findings.

Differences in the subjective and motivational properties of alcohol across alcohol use severity: application of a novel translational human laboratory paradigm

The Allostatic Model proposes that Alcohol Use Disorder (AUD) is associated with a transition in the motivational structure of alcohol drinking: from positive reinforcement in early-stage drinking to negative reinforcement in late-stage dependence. However, direct empirical support for this preclinical model from human experiments is limited. This study tests predictions derived from the Allostatic Model in humans. Specifically, this study tested whether alcohol use severity (1) independently predicts subjective responses to alcohol (SR; comprised of stimulation/hedonia, negative affect, sedation and craving domains), and alcohol self-administration and 2) moderates associations between domains of SR and alcohol self-administration. Heavy drinking participants ranging in severity of alcohol use and problems (N = 67) completed an intravenous alcohol administration paradigm combining an alcohol challenge (target BrAC = 60 mg%), with progressive ratio self-administration. Alcohol use severity was associated with greater baseline negative affect, sedation, and craving but did not predict changes in any SR domain during the alcohol challenge. Alcohol use severity also predicted greater self-administration. Craving during the alcohol challenge strongly predicted self-administration and sedation predicted lower self-administration. Neither stimulation, nor negative affect predicted self-administration. This study represents a novel approach to translating preclinical neuroscientific theories to the human laboratory. As expected, craving predicted self-administration and sedation was protective. Contrary to the predictions of the Allostatic Model, however, these results were inconsistent with a transition from positively to negatively reinforced alcohol consumption in severe AUD. Future studies that assess negative reinforcement in the context of an acute stressor are warranted.

Extraversion and behavioural approach system in stimulus analysis and motor response initiation

In this study, we attempt to validate previous findings on extraversion-related differences in speed of sensorimotor processing and to extend them into Behavioural Approach System (BAS) subtraits within the framework of the revised Reinforcement Sensitivity Theory (rRST) of personality. Here, we assessed psychological traits of extraversion (E), four BAS facets (Goal-Drive Persistence, BAS-GDP; Reward Interest, BAS-RI; Reward Reactivity, BAS-RR; Impulsivity, BAS-I), Behavioural Inhibition System (BIS), and Fight-Flight-Freeze System (FFFS) in 51 volunteers (28 women). Stimulus-locked lateralized readiness potential (S-LRP), response-locked LRP (R-LRP), stimulus-locked and response-locked forearm electromyogram (S-EMG and R-EMG), and P3 components of the event-related potentials (ERPs), were recorded during the performance of a two-choice Go/NoGo visual letter-digit discrimination task varying in task difficulty. High extraverts, relative to introverts and individuals high relative to low on BAS-RI, were more likely to exhibit shorter S-LRP latencies and stimulus- and response-locked EMG latencies. Additionally, high BAS-I had a shorter R-RLP latency than low BAS-I participants for the difficult task. High FFFS levels were associated with longer S-LRP and S-EMG latencies, while high BIS levels had larger response accuracy. Extraverts, relative to introverts, along with those high relative to low on BAS-RR and BAS-I, exhibited smaller P3 amplitudes. The faster cortical premotor initiation, found in individuals high on extraversion, BAS-RI and low on FFFS, may account for their faster peripheral motor response initiation and execution. Smaller P3 amplitudes in extraverts and individuals high on BAS-RR and BAS-I may indicate reduced perceptual processing capacity in these individuals.

Preclinical evaluation of avermectins as novel therapeutic agents for alcohol use disorders

The deleterious effects of alcohol use disorders (AUDs) on human health have been documented worldwide. The enormous socioeconomic burden coupled with lack of efficacious pharmacotherapies underlies the need for improved treatment strategies. At present, there is a growing body of preclinical evidence that demonstrates the potential of avermectins [ivermectin (IVM), selamectin (SEL), abamectin (ABM), and moxidectin (MOX)] in treatment of AUDs. Avermectins are derived by fermentation of soil micro-organism, Streptomyces avermitilis, and have been extensively used for treatment of parasitic infections. From the mechanistic standpoint, avermectins are positive modulators of purinergic P2X4 receptors (P2X4Rs). P2X4Rs belong to P2X superfamily of cation-permeable ion channels gated by adenosine 5'-triphosphate (ATP). Building evidence has implicated a role for P2X4Rs in regulation of ethanol intake and that ethanol can inhibit ATP-gated currents in P2X4Rs. Investigations using recombinant cell models and animal models of alcohol drinking have reported that IVM, ABM, and MOX, but not SEL, were able to antagonize the inhibitory effects of ethanol on P2X4Rs in vitro and reduce ethanol intake in vivo. Furthermore, IVM was shown to reduce ethanol consumption via P2X4R potentiation in vivo, supporting the involvement of P2X4Rs in IVM's anti-alcohol effects and that P2X4Rs can be used as a platform for developing novel anti-alcohol compounds. Taken together, these findings support the utility of avermectins as a novel class of drug candidates for treatment of AUDs.

Precision Medicine in Alcohol Dependence: A Controlled Trial Testing Pharmacotherapy Response Among Reward and Relief Drinking Phenotypes

Randomized trials of medications for alcohol dependence (AD) often report no differences between active medications. Few studies in AD have tested hypotheses regarding which medication will work best for which patients (ie, precision medicine). The PREDICT study tested acamprosate and naltrexone vs placebo in 426 randomly assigned AD patients in a 3-month treatment. PREDICT proposed individuals whose drinking was driven by positive reinforcement (ie, reward drinkers) would have a better treatment response to naltrexone, whereas individuals whose drinking was driven by negative reinforcement (ie, relief drinkers) would have a better treatment response to acamprosate. The goal of the current analysis was to test this precision medicine hypothesis of the PREDICT study via analyses of subgroups. Results indicated that four phenotypes could be derived using the Inventory of Drinking Situations, a 30-item self-report questionnaire. These were high reward/high relief, high reward/low relief, low reward/high relief, and low reward/low relief phenotypes. Construct validation analyses provided strong support for the validity of these phenotypes. The subgroup of individuals who were predominantly reward drinkers and received naltrexone vs placebo had an 83% reduction in the likelihood of any heavy drinking (large effect size). Cutoff analyses were done for clinical applicability: individuals are reward drinkers and respond to naltrexone if their reward score was higher than their relief score AND their reward score was between 12 and 31. Using naltrexone with individuals who are predominantly reward drinkers produces significantly higher effect sizes than prescribing the medication to a more heterogeneous sample.

The neural correlates of the unified percept of alcohol-related craving: a fMRI and EEG study

Alcohol addiction is accompanied by aberrant neural activity. Previously, task-based fMRI and resting-state EEG studies have revealed that craving, a critical component of addiction, is linked to abnormal activity in cortical regions including the dorsal anterior cingulate cortex (dACC), nucleus accumbens (NAcc), posterior cingulate cortex (PCC) and pregenual anterior cingulate cortex (pgACC), etc. In this study, we combine these two imaging techniques to investigate a group of alcohol-addicted patients and provide convergent evidence for the neural correlates of craving not only in alcohol but substance abuse in general. We observe abnormal BOLD signal levels in the dACC, NAcc, pgACC, PCC, amygdala, and parahippocampus (PHC) in a cue-reactivity fMRI experiment. These findings are consistent with increased beta-band activity in the dACC and pgACC in resting-state EEG. We further observe desynchronization characterized by decreased functional connectivity in cue-based fMRI and hypersynchronization characterized by increased functional connectivity between these regions in the theta frequency band. The results of our study show a consistent pattern of alcohol craving elicited by external cues and internal desires. Given the advantage of superior spatial and temporal resolution, we hypothesize a "central craving network" that integrates the different aspects of alcohol addiction into a unified percept.

The Modulation of the Startle Reflex as Predictor of Alcohol Use Disorders in a Sample of Heavy Drinkers: A 4-Year Follow-Up Study

BACKGROUND

Previous studies demonstrated that patients with alcohol use disorders (AUDs) show altered startle reflex responses to alcohol-related stimuli. However, there is little information about the role of these altered responses in the development of AUDs. This study examined the startle reflex response to different visual stimuli and the role of these patterns in the development of AUDs in a 4-year follow-up.

METHODS

Two hundred and thirty-nine (nondependent) heavy-drinking participants were selected. In the baseline period, the startle reflex responses to alcohol-related, aversive, appetitive, and neutral pictures were assessed. Startle reflex responses to these pictures were used as predictive variables. Status drinking (alcohol dependence and nondependence) assessed at 4-year follow-up was used as outcome measure.

RESULTS

At the 4-year follow-up assessment, 46% of participants fulfilled DSM-IV alcohol abuse or dependence criteria. Alcohol dependence status was predicted by an attenuated startle reflex response to alcohol-related and aversive pictures.

CONCLUSIONS

This study revealed that an attenuated modulation of startle reflex response to alcohol-related and aversive stimuli could be used as a clinical marker to predict the development of AUDs in participants with previous alcohol consumption.

Effects of naltrexone are influenced by childhood adversity during negative emotional processing in addiction recovery

Naltrexone is an opioid receptor antagonist used in the management of alcohol dependence. Although the endogenous opioid system has been implicated in emotion regulation, the effects of mu-opioid receptor blockade on brain systems underlying negative emotional processing are not clear in addiction. Individuals meeting criteria for alcohol dependence alone (n=18, alcohol) and in combination with cocaine and/or opioid dependence (n=21, alcohol/drugs) and healthy individuals without a history of alcohol or drug dependence (n=21) were recruited. Participants were alcohol and drug abstinent before entered into this double-blind, placebo-controlled, randomized, crossover study. Functional magnetic resonance imaging was used to investigate brain response while viewing aversive and neutral images relative to baseline on 50 mg of naltrexone and placebo. We found that naltrexone modulated task-related activation in the medial prefrontal cortex and functional connectivity between the anterior cingulate cortex and the hippocampus as a function of childhood adversity (for aversive versus neutral images) in all groups. Furthermore, there was a group-by-treatment-by-condition interaction in the right amygdala, which was mainly driven by a normalization of response for aversive relative to neutral images under naltrexone in the alcohol/drugs group. We conclude that early childhood adversity is one environmental factor that influences pharmacological response to naltrexone. Pharmacotherapy with naltrexone may also have some ameliorative effects on negative emotional processing in combined alcohol and drug dependence, possibly due to alterations in endogenous opioid transmission or the kappa-opioid receptor antagonist actions of naltrexone.

Behavioral activation and inhibition system's role in predicting addictive behaviors of patients with bipolar disorder of Roozbeh Psychiatric Hospital

Background:

Nowadays, prevalence of addictive behaviors among bipolar patients is considered to be a serious health threat by the World Health Organization. The aim of this study is to investigate the role of behavioral activation and inhibition systems in predicting addictive behaviors of male patients with bipolar disorder at the Roozbeh Psychiatric Hospital.

Materials and Methods:

The research method used in this study is correlation. The study population consisted of 80 male patients with bipolar disorder referring to the psychiatrics clinics of Tehran city in 2014 who were referred to the Roozbeh Psychiatric Hospital. To collect data, the international and comprehensive inventory diagnostic interview, behavioral activation and inhibition systems scale, and addictive behaviors scale were used.

Results:

The results showed that there is a positive and significant relationship between behavioral activation systems and addictive behaviors (addictive eating, alcohol addiction, television addiction, cigarette addiction, mobile addiction, etc.). In addition, correlation between behavioral inhibition systems and addictive behaviors (addictive eating, alcohol addiction, TV addiction, cigarette addiction, mobile addiction) is significantly negative. Finally, regression analysis showed that behavioral activation and inhibition systems could significantly predict 47% of addictive behaviors in patients with bipolar disorder.

Conclusions:

It can be said that the patients with bipolar disorder use substance and addictive behaviors for enjoyment and as pleasure stimulants; they also use substances to suppress unpleasant stimulants and negative emotions. These results indicate that behavioral activation and inhibition systems have an important role in the incidence and exacerbation of addictive behaviors. Therefore, preventive interventions in this direction seem to be necessary.

The Reasons for Heavy Drinking Questionnaire: Factor Structure and Validity in Alcohol-Dependent Adults Involved in Clinical Trials

OBJECTIVE

People consume alcohol at problematic levels for many reasons. These different motivational pathways may have different biological underpinnings. Valid, brief measures that discriminate individuals' reasons for drinking could facilitate inquiry into whether varied drinking motivations account for differential response to pharmacotherapies for alcohol use disorders. The current study evaluated the factor structure and predictive validity of a brief measure of alcohol use motivations developed for use in randomized clinical trials, the Reasons for Heavy Drinking Questionnaire (RHDQ).

METHOD

The RHDQ was administered before treatment to 265 participants (70% male) with alcohol dependence according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, in three pharmacotherapy randomized clinical trials. Principal components analysis was used in half the sample to determine the RHDQ factor structure. This structure was verified with confirmatory factor analysis in the second half of the sample. The factors derived from this analysis were evaluated with respect to alcohol dependence severity indices.

RESULTS

A two-factor solution was identified. Factors were interpreted as Reinforcement and Normalizing. Reinforcement scores were weakly to moderately associated with severity, whereas normalizing scores were moderately to strongly associated with severity. In all cases in which significant associations between RHDQ scores and severity indices were observed, the relationship was significantly stronger for normalizing than for reinforcing.

CONCLUSIONS

The RHDQ is a promising brief assessment of motivations for heavy alcohol use, particularly in the context of randomized clinical trials. Additional research should address factor structure stability in non-treatment-seeking individuals and the RHDQ's utility in detecting and accounting for changes in drinking behavior, including in response to intervention.

The CRF1 Antagonist Verucerfont in Anxious Alcohol-Dependent Women: Translation of Neuroendocrine, But not of Anti-Craving Effects

Blockade of corticotropin-releasing factor receptor 1 (CRF1) suppresses stress-induced alcohol seeking in rodents, but clinical translation remains. Here, we first showed that the CRF1 antagonist verucerfont potently blocks hypothalamic-pituitary adrenal (HPA) axis activation in adrenalectomized rats. We then evaluated verucerfont for its ability to block HPA axis activation and reduce stress-induced alcohol craving in alcohol-dependent patients. Anxious, alcohol-dependent women (age 21-65 years, n=39) were admitted to the NIH Clinical Center and completed withdrawal treatment before enrollment if needed. One-week single-blind placebo was followed by randomized double-blind verucerfont (350 mg per day) or placebo for 3 weeks. Verucerfont effects on the HPA axis were evaluated using the dexamethasone-CRF test. Craving was evaluated using two established protocols, one that combines a social stressor with physical alcohol cue exposure, and one that uses guided imagery to present personalized stress, alcohol, or neutral stimuli. An fMRI session examined brain responses to negative affective stimuli and alcohol cues. In contrast to our recent observations with another CRF1 antagonist, pexacerfont, verucerfont potently blocked the HPA axis response to the dexamethasone-CRF test, but left alcohol craving unaffected. Right amygdala responses to negative affective stimuli were significantly attenuated by verucerfont, but responses to alcohol-associated stimuli were increased in some brain regions, including left insula. Discontinuation rates were significantly higher in the verucerfont group. Our findings provide the first translational evidence that CRF1 antagonists with slow receptor dissociation kinetics may have increased efficacy to dampen HPA axis responses. The findings do not support a clinical efficacy of CRF1 blockade in stress-induced alcohol craving and relapse.

Anterior Cingulate Implant for Obsessive-Compulsive Disorder

BACKGROUND

Obsessive-compulsive disorder (OCD) is a brain disorder with a lifetime prevalence of 2.3%, causing severe functional impairment as a result of anxiety and distress, persistent and repetitive, unwanted, intrusive thoughts (obsessions), and repetitive ritualized behavior (compulsions). Approximately 40%-60% of patients with OCD fail to satisfactorily respond to standard treatments. Intractable OCD has been treated by anterior capsulotomy and cingulotomy, but more recently, neurostimulation approaches have become more popular because of their reversibility.

OBJECTIVE

Implants for OCD are commonly being used, targeting the anterior limb of the internal capsula or the nucleus accumbens, but an implant on the anterior cingulate cortex has never been reported.

METHODS

We describe a patient who was primarily treated for alcohol addiction, first with transcranial magnetic stimulation, then by implantation of 2 electrodes overlying the rostrodorsal part of the anterior cingulate cortex bilaterally.

RESULTS

Her alcohol addiction developed as she was relief drinking to self-treat her OCD, anxiety, and depression. After the surgical implant, she underwent placebo stimulation followed by real stimulation of the dorsal anterior cingulate cortex, which dramatically improved her OCD symptoms (decrease of 65.5% on the Yale-Brown Obsessive Compulsive Drinking Scale) as well as her alcohol craving (decrease of 87.5%) after 36 weeks of treatment. Although there were improvements in all the scores, there was only a modest reduction in the patient's weekly alcohol consumption (from 50 units to 32 units).

CONCLUSIONS

Based on these preliminary positive results we propose to further study the possible beneficial effect of anterior cingulate cortex stimulation for intractable OCD.

Pavlovian-to-instrumental transfer effects in the nucleus accumbens relate to relapse in alcohol dependence

In detoxified alcohol-dependent patients, alcohol-related stimuli can promote relapse. However, to date, the mechanisms by which contextual stimuli promote relapse have not been elucidated in detail. One hypothesis is that such contextual stimuli directly stimulate the motivation to drink via associated brain regions like the ventral striatum and thus promote alcohol seeking, intake and relapse. Pavlovian-to-Instrumental-Transfer (PIT) may be one of those behavioral phenomena contributing to relapse, capturing how Pavlovian conditioned (contextual) cues determine instrumental behavior (e.g. alcohol seeking and intake). We used a PIT paradigm during functional magnetic resonance imaging to examine the effects of classically conditioned Pavlovian stimuli on instrumental choices in n = 31 detoxified patients diagnosed with alcohol dependence and n = 24 healthy controls matched for age and gender. Patients were followed up over a period of 3 months. We observed that (1) there was a significant behavioral PIT effect for all participants, which was significantly more pronounced in alcohol-dependent patients; (2) PIT was significantly associated with blood oxygen level-dependent (BOLD) signals in the nucleus accumbens (NAcc) in subsequent relapsers only; and (3) PIT-related NAcc activation was associated with, and predictive of, critical outcomes (amount of alcohol intake and relapse during a 3 months follow-up period) in alcohol-dependent patients. These observations show for the first time that PIT-related BOLD signals, as a measure of the influence of Pavlovian cues on instrumental behavior, predict alcohol intake and relapse in alcohol dependence.

Anterior Cingulate Implant for Alcohol Dependence

BACKGROUND AND IMPORTANCE:

Alcohol dependence is related to dysfunctional brain processes, in which a genetic background and environmental factors shape brain mechanisms involved with alcohol consumption. Craving, a major component determining relapses in alcohol abuse, has been linked to abnormal brain activity.

CLINICAL PRESENTATION:

We report the results of a treatment-intractable, alcohol-addicted patient with associated agoraphobia and anxiety. Functional imaging studies consisting of functional magnetic resonance imaging and resting-state electroencephalogram were performed as a means to localize craving-related brain activation and for identification of a target for repetitive transcranial magnetic stimulation and implant insertion. Repetitive transcranial magnetic stimulation of the dorsal anterior cingulate cortex with a double-cone coil transiently suppressed his very severe alcohol craving for up to 6 weeks. For ongoing stimulation, 2 “back-to-back” paddle electrodes were implanted with functional magnetic resonance imaging neuronavigation guidance for bilateral dorsal anterior cingulate cortex stimulation. Using a recently developed novel stimulation design, burst stimulation, a quick improvement was obtained on craving, agoraphobia, and associated anxiety without the expected withdrawal symptoms. The patient has remained free of alcohol intake and relieved of agoraphobia and anxiety for over 18 months, associated with normalization of his alpha and beta activity on electroencephalogram in the stimulated area. He perceives a mental freedom by not being constantly focused on alcohol.

CONCLUSION:

This case report proposes a new pathophysiology-based target for the surgical treatment of alcohol dependence and suggests that larger studies are warranted to explore this potentially promising avenue for the treatment of intractable alcohol dependence with or without anxiety and agoraphobia.

Changes in Nutrition-Related Behaviors in Alcohol-Dependent Patients After Outpatient Detoxification: The Role of Chocolate

BACKGROUND

Previous studies have reported changes in nutrition-related behaviors in alcohol-dependent patients after alcohol detoxification, but prospective studies assessing the effects of these changes on maintaining abstinence are lacking.

OBJECTIVES

To assess changes in craving and consumption of chocolate and other sweets over time up to six months after outpatient alcohol detoxification treatment and to detect differences in abstinent versus nonabstinent patients.

METHODS

One hundred and fifty alcohol-dependent patients were included in this prospective observational study. Participants completed self-report questionnaires on nutrition-related behaviors and craving before detoxification treatment (baseline, t1), one week (t2), one month (t3), and six months later (t4).

RESULTS

Significant changes in craving for and consumption of chocolate as well as in craving for other sweets were observed over time. Increases were most prominent within the first month. Patients who remained abstinent until t3 consumed three times more chocolate than nonabstainers. One quarter of the patients switched from being rare (t1) to frequent (t3) chocolate eaters, and 84% of these remained abstinent until t3. No significant correlations were found between craving for alcohol and craving for or consumption of chocolate or other sweets.

CONCLUSIONS/IMPORTANCE

In the first month after outpatient alcohol detoxification treatment, significant changes in nutrition-related behaviors were observed. These changes were not associated with alcohol craving. For a subgroup, increasing the frequency of chocolate consumption might be a temporary protective factor with respect to alcohol relapse.