Addiction is driven by excessive goal-directed drug choice under negative affect: translational critique of habit and compulsion theory

Negative Affect, Sensation Seeking, and Adolescent Substance Use Development: The Moderating Role of Executive Function

It is unknown how the Addictions Neuroclinical Assessment markers-negative affect, sensation seeking, and executive function-contribute to substance use development. This study examined whether associations of negative affect and sensation seeking with substance use vary by executive function. Participants were 167 adolescents (47% female) who participated annually for four years (Mage = 14.07, SDage = 0.54 at Time 1). There were within-person bidirectional associations between higher negative affect and higher substance use for adolescents with lower executive function. Adolescents with higher sensation seeking at age 14 exhibited increasing substance use trajectories from age 14 to 17, regardless of executive function level. Negative affect and substance use influence each other within individuals, whereas sensation seeking predicts substance use between individuals.

Transfer from goal-directed behavior to stimulus-response habits and its modulation by acute stress in individuals with risky gaming behavior

Habitual responses towards addiction-related cues play a relevant role in the development and maintenance of addictions. Such automatic responses may be more likely under stress, as stress has been shown to induce a shift from goal-directed to habitual behavior. The current study investigated these mechanisms in risky gaming behavior. Individuals with risky gaming behavior (n = 68), as established by a structured clinical interview, and a matched control group (n = 67) completed a Pavlovian-to-Instrumental Transfer (PIT) paradigm with gaming-related cues and rewards. After the Pavlovian training, participants underwent a stress (Trier Social Stress Test) or control condition before performing the instrumental training and the transfer phase of the PIT paradigm. To assess habitual behavior, the gaming-related rewards were devalued after half of the transfer phase. In both groups, gaming-related cues enhanced the choice of the gaming-related reward and this gaming PIT effect was reduced, however, not eliminated by the devaluation. Unexpectedly, stress did not significantly increase responding for the gaming-related reward in participants aware of the stimulus-outcome associations, however seemed to enhance habitual responding in unaware participants. Our findings underline the relevance of gaming-related cues in triggering habitual responses, which may undermine attempts to change a problematic gaming behavior.

Choice of alcohol over a natural reward: an experimental study in light and heavy social drinkers

RATIONALE & OBJECTIVES

A core symptom of alcohol use disorder (AUD) is a progressively increased choice of alcohol over alternative rewards despite negative consequences. Here, we investigated choice between personalized alcohol vs. natural rewards in a laboratory setting, and compared this behavior between non-treatment-seeking heavy drinkers and light social drinkers.

METHODS

30 light social drinkers (15 men drinking < 15 drinks/week and 15 women drinking < 10 drinks/week) and 30 heavy, non-treatment-seeking drinkers (drinking more than these levels; 15 women). In the Concurrent Choice Alcohol Food (CCAF) task, participants chose between individually tailored images of alcohol and snack rewards and collected points towards the respective reward. To assess cost sensitivity, points associated to the images varied so that they favored alcohol or snack, or were equal, creating three relative point levels.

RESULTS

Choice preference for alcohol was strongly correlated with Alcohol Use Disorder Identification Test (AUDIT) scores, supporting the external validity of the choice procedure. Compared to light drinkers, heavy drinkers showed increased choice preference for alcohol, as indicated by a between-group difference in points of subjective equality, a metric that quantifies the relative point level at which alcohol and snacks were equally likely to be chosen. In both groups, choice preference strongly depended on the relative point level of alcohol compared to snacks, suggesting that responding for alcohol in heavy drinkers was sensitive to costs.

CONCLUSIONS

Our results replicate previous findings of a relationship between self-reported alcohol use and choice preference for alcohol. We also found that choice behavior was strongly dependent on relative cost of alcohol in both groups, although price sensitivity was lower in heavy compared to light drinkers. An increased choice preference for alcohol in heavy drinkers suggests that they attribute a higher relative reinforcing value to alcohol compared to natural rewards.

Reward processing in young people with self-harm behaviour

Twenty percent of young people report a lifetime presence of self-harm (SH) behaviour, associated with negative health and functional outcomes. Understanding the underlying cognitive mechanisms is needed to develop targeted early interventions. Reward processing biases may underlie SH, aligning with accounts of the behaviour acquiring "addictive" characteristics. However, the specific nature of such biases remains unclear, particularly its relationship with negative affect (NA) that frequently triggers SH. In Study 1, we compared young people (aged 16-25) with SH to a group with NA but no SH history and a healthy control group on performance of a novel Incentive Delay Task (IDT), with SH-related (SH trials), positive social (social trials) or monetary images (money trials) as stimuli. In Study 2, a different sample of SH and HC participants completed the same IDT following NA induction via an online Trier Social Stress Test. For both studies, we hypothesised faster and more correct responses in the SH group than control groups on SH trials. Contradicting our hypothesis, there were no significant between-group differences in IDT performance on SH, social and money trials in either study. Certain SH characteristics (positive reinforcement, SH mental imagery, urge) were significantly correlated with better performance on SH trials in SH participants. Thus, broadly SH behaviour may not be underpinned by motivational biases towards SH-related cues or naturalistic rewards. Future studies should clarify whether incentivisation of SH-related cues instead explains individual differences in SH behaviour and its relation with treatment and prognosis.

Sex differences in cigarette smoking following a mindfulness-based cessation randomized controlled trial

Some interventions for smoking cessation such as quit smoking aids show sex-specific effects on outcomes, but behavioral interventions such as mindfulness-based interventions (MBIs) for smoking cessation lack formal reporting of sex-intervention tests of interaction to date. To address this gap, we conducted a secondary analysis of a RCT dataset (N = 213), recruiting participants from California, to statistically test a sex-intervention interaction effect on complete 7-day point prevalence abstinence (PPA), proportion of days abstinent, and daily cigarettes smoked. Smoking was assessed using the timeline follow back method spanning the four weeks following a daily 14-day app-based intervention and a planned smoking quit date immediately following the intervention phase. All models adjusted for baseline nicotine dependence. The study groups had comparable sex proportions (MBI: 56 % female; control: 55 % female) and the ratio of outcome assessment completion by group was not dependent on sex. Adjusted analyses revealed a significant sex-intervention interaction effect for daily cigarettes smoked ([female coded 1]: two-way interaction effect IRR = 0.59, 95 % CI: 0.46-0.77, p < 0.0001; effect for female: IRR = 0.68, 95 % CI: 0.57-0.81, effect for male: IRR = 1.14, 95 % CI: 0.95-1.37), but not for complete 7-day PPA ([female coded 1] two-way interaction effect OR = 1.24, 95 % CI: 0.31-4.89, p = 0.76) or proportion of total days abstinent ([female coded 1] two-way interaction effect OR = 1.97, 95 % CI: 0.53-7.37, p = 0.31). Females, but not males, allocated to a daily app-based MBI with a quit plan and quit aid workbook smoked fewer cigarettes per day compared to females in the control group. Males, but not females, showed significantly less use of the MBI app compared to the control app.

A study on the mediating-moderate effect of the types of illicit drugs on mental health in China

Background

In China, over 5 million people have been identified and registered by the public security institutions for using illicit drugs. The aim of this study is to compare the influence of different types of illicit drugs on the self-reported mental health of Chinese people. In particular, we want to assess the damage of Heroin, Methamphetamine and Ketamine to mental health in a social environment where drug use is strictly regulated.

Methods

The study is based on survey with 6,906 people who use drugs in Guangdong province, China. Risk of mental health issue is measured using the Brief Symptoms Inventory 18 (BSI-18) Scale, and a higher BSI-18 score indicates more severe mental health problems. The data was analyzed through multilevel regression analysis, propensity score matching analysis and mediation analysis.

Results

The three major types of illicit drugs have both moderating and mediating effects on the length of drug-use history, that Heroin use leads to longer drug-use duration, while Ketamine use causes more damage on mental health per unit time of drug-use duration. Average duration of Methamphetamine use is 0.7 year shorter than average duration of Heroin use, and average duration of Ketamine use is 1.7 year shorter than average duration of Heroin use. For each year of increase of drug-use duration, Ketamine use leads to 1.2 times more of BSI score increase than Heroin use, and 2.3 times more of BSI score increase than Methamphetamine use.

Conclusion

These three drugs are associated with severe mental health issue in a society with strict drug regulation. Attention should be paid to the mental health of people regardless of the type of drugs they use.

Neuroimaging Biomarkers in Addiction

As a neurobiological process, addiction involves pathological patterns of engagement with substances and a range of behaviors with a chronic and relapsing course. Neuroimaging technologies assess brain activity, structure, physiology, and metabolism at scales ranging from neurotransmitter receptors to large-scale brain networks, providing unique windows into the core neural processes implicated in substance use disorders. Identified aberrations in the neural substrates of reward and salience processing, response inhibition, interoception, and executive functions with neuroimaging can inform the development of pharmacological, neuromodulatory, and psychotherapeutic interventions to modulate the disordered neurobiology. Based on our systematic search, 409 protocols registered on ClinicalTrials.gov include the use of one or more neuroimaging paradigms as an outcome measure in addiction, with the majority (N=268) employing functional magnetic resonance imaging (fMRI), followed by positron emission tomography (PET) (N=71), electroencephalography (EEG) (N=50), structural magnetic resonance imaging (MRI) (N=35) and magnetic resonance spectroscopy (MRS) (N=35). Furthermore, in a PubMed systematic review, we identified 61 meta-analyses including 30 fMRI, 22 structural MRI, 8 EEG, 7 PET, and 3 MRS meta-analyses suggesting potential biomarkers in addictions. These studies can facilitate the development of a range of biomarkers that may prove useful in the arsenal of addiction treatments in the coming years. There is evidence that these markers of large-scale brain structure and activity may indicate vulnerability or separate disease subtypes, predict response to treatment, or provide objective measures of treatment response or recovery. Neuroimaging biomarkers can also suggest novel targets for interventions. Closed or open loop interventions can integrate these biomarkers with neuromodulation in real-time or offline to personalize stimulation parameters and deliver the precise intervention. This review provides an overview of neuroimaging modalities in addiction, potential neuroimaging biomarkers, and their physiologic and clinical relevance. Future directions and challenges in bringing these putative biomarkers from the bench to the bedside are also discussed.

Value-based decision-making in regular alcohol consumers following experimental manipulation of alcohol value

BACKGROUND

Devaluation of alcohol leads to reductions in alcohol choice and consumption; however, the cognitive mechanisms that underpin this relationship are not well-understood. In this study we applied a computational model of value-based decision-making (VBDM) to decisions made about alcohol and alcohol-unrelated cues following experimental manipulation of alcohol value.

METHOD

Using a pre-registered within-subject design, thirty-six regular alcohol consumers (≥14 UK units per week) completed a two-alternative forced choice task where they chose between two alcohol images (in one block) or two soft drink images (in a different block) after watching videos that emphasised the positive (alcohol value), and separately, the negative (alcohol devalue) consequences of alcohol. On each block, participants pressed a key to select the image depicting the drink they would rather consume. A drift-diffusion model (DDM) was fitted to reaction time and choice data to estimate evidence accumulation (EA) processes and response thresholds during the different blocks in each experimental condition.

FINDINGS

In the alcohol devalue condition, soft drink EA rates were significantly higher compared to alcohol EA rates (p = 0.04, d = 0.31), and compared to soft drink EA rates in the alcohol value condition (p = 0.01, d = 0.38). However, EA rates for alcoholic drinks and response thresholds (for either drink type) were unaffected by the experimental manipulation.

CONCLUSIONS

In line with behavioural economic models of addiction that emphasise the important role of alternative reinforcement, experimentally manipulating alcohol value is associated with changes in the internal cognitive processes that precede soft drink choice.

Random interval schedule of reinforcement influences punishment resistance for cocaine in rats

In an animal model of compulsive drug use, a subset of rats continues to self-administer cocaine despite footshock consequences and is considered punishment resistant. We recently found that punishment resistance is associated with habits that persist under conditions that typically encourage a transition to goal-directed control. Given that random ratio (RR) and random interval (RI) schedules of reinforcement influence whether responding is goal-directed or habitual, we investigated the influence of these schedules on punishment resistance for cocaine or food. Male and female Sprague Dawley rats were trained to self-administer either intravenous cocaine or food pellets on a seeking-taking chained schedule of reinforcement, with the seeking lever requiring completion of either an RR20 or RI60 schedule. Rats were then given four days of punishment testing with footshock administered at the completion of seeking on a random one-third of trials. For cocaine-trained rats, the RI60 schedule led to greater punishment resistance (i.e., more trials completed) than the RR20 schedule in males and females. For food-trained rats, the RI60 schedule led to greater punishment resistance (i.e., higher reward rates) than the RR20 schedule in female rats, although male rats showed punishment resistance on both RR20 and RI60 schedules. For both cocaine and food, we found that seeking responses were suppressed to a greater degree than reward rate with the RI60 schedule, whereas response rate and reward rate were equally suppressed with the RR20 schedule. This dissociation between punishment effects on reward rate and response rate with the RI60 schedule can be explained by the nonlinear relation between these variables on RI schedules, but it does not account for the enhanced resistance to punishment. Overall, the results show greater punishment resistance with the RI60 schedule as compared to the RR20 schedule, indicating that schedules of reinforcement are an influencing factor on resistance to negative consequences.

Learning and memory processes in behavioural addiction: A systematic review

Similar to addictive substances, addictive behaviours such as gambling and gaming are associated with maladaptive modulation of key brain areas and functional networks implicated in learning and memory. Therefore, this review sought to understand how different learning and memory processes relate to behavioural addictions and to unravel their underlying neural mechanisms. Adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we systematically searched four databases - PsycINFO, PubMed, Scopus, and Web of Science using the agreed-upon search string. Findings suggest altered executive function-dependent learning processes and enhanced habit learning in behavioural addiction. Whereas the relationship between working memory and behavioural addiction is influenced by addiction type, working memory aspect, and task nature. Additionally, long-term memory is incoherent in individuals with addictive behaviours. Consistently, neurophysiological evidence indicates alterations in brain areas and networks implicated in learning and memory processes in behavioural addictions. Overall, the present review argues that, like substance use disorders, alteration in learning and memory processes may underlie the development and maintenance of behavioural addictions.

Cortico-striatal white-matter connectivity underlies the ability to exert goal-directed control

The balance between goal-directed and habitual control has been proposed to determine the flexibility of instrumental behaviour, in both humans and animals. This view is supported by neuroscientific studies that have implicated dissociable neural pathways in the ability to flexibly adjust behaviour when outcome values change. A previous Diffusion Tensor Imaging study provided preliminary evidence that flexible instrumental performance depends on the strength of parallel cortico-striatal white-matter pathways previously implicated in goal-directed and habitual control. Specifically, estimated white-matter strength between caudate and ventromedial prefrontal cortex correlated positively with behavioural flexibility, and posterior putamen-premotor cortex connectivity correlated negatively, in line with the notion that these pathways compete for control. However, the sample size of the original study was limited, and so far, there have been no attempts to replicate these findings. In the present study, we aimed to conceptually replicate these findings by testing a large sample of 205 young adults to relate cortico-striatal connectivity to performance on the slips-of-action task. In short, we found only positive neural correlates of goal-directed performance, including striatal connectivity (caudate and anterior putamen) with the dorsolateral prefrontal cortex. However, we failed to provide converging evidence for the existence of a neural habit system that puts limits on the capacity for flexible, goal-directed action. We discuss the implications of our findings for dual-process theories of instrumental action.

Bad habits-good goals? Meta-analysis and translation of the habit construct to alcoholism

Excessive alcohol consumption remains a global public health crisis, with millions suffering from alcohol use disorder (AUD, or simply "alcoholism"), leading to significantly reduced life expectancy. This review examines the interplay between habitual and goal-directed behaviors and the associated neurobiological changes induced by chronic alcohol exposure. Contrary to a strict habit-goal dichotomy, our meta-analysis of the published animal experiments combined with a review of human studies reveals a nuanced transition between these behavioral control systems, emphasizing the need for refined terminology to capture the probabilistic nature of decision biases in individuals with a history of chronic alcohol exposure. Furthermore, we distinguish habitual responding from compulsivity, viewing them as separate entities with diverse roles throughout the stages of the addiction cycle. By addressing species-specific differences and translational challenges in habit research, we provide insights to enhance future investigations and inform strategies for combatting AUD.

The Small G-Protein Rac1 in the Dorsomedial Striatum Promotes Alcohol-Dependent Structural Plasticity and Goal-Directed Learning in Mice

The small G-protein Ras-related C3 botulinum toxin substrate 1 (Rac1) promotes the formation of filamentous actin (F-actin). Actin is a major component of dendritic spines, and we previously found that alcohol alters actin composition and dendritic spine structure in the nucleus accumbens (NAc) and the dorsomedial striatum (DMS). To examine if Rac1 contributes to these alcohol-mediated adaptations, we measured the level of GTP-bound active Rac1 in the striatum of mice following 7 weeks of intermittent access to 20% alcohol. We found that chronic alcohol intake activates Rac1 in the DMS of male mice. In contrast, Rac1 is not activated by alcohol in the NAc and DLS of male mice or in the DMS of female mice. Similarly, closely related small G-proteins are not activated by alcohol in the DMS, and Rac1 activity is not increased in the DMS by moderate alcohol or natural reward. To determine the consequences of alcohol-dependent Rac1 activation in the DMS of male mice, we inhibited endogenous Rac1 by infecting the DMS of mice with an adeno-associated virus (AAV) expressing a dominant negative form of the small G-protein (Rac1-DN). We found that overexpression of AAV-Rac1-DN in the DMS inhibits alcohol-mediated Rac1 signaling and attenuates alcohol-mediated F-actin polymerization, which corresponded with a decrease in dendritic arborization and spine maturation. Finally, we provide evidence to suggest that Rac1 in the DMS plays a role in alcohol-associated goal-directed learning. Together, our data suggest that Rac1 in the DMS plays an important role in alcohol-dependent structural plasticity and aberrant learning.

The influence of drug class on reward in substance use disorders

In the United States, the societal costs associated with drug use surpass $500 billion annually. The rewarding and reinforcing properties that drive the use of these addictive substances are typically examined concerning the neurobiological effects responsible for their abuse potential. In this review, terms such as "abuse potential," "drug," and "addictive properties" are used due to their relevance to the methodological, theoretical, and conceptual framework for understanding the phenomenon of drug-taking behavior and the associated body of preclinical and clinical literature. The use of these terms is not intended to cast aspersions on individuals with substance use disorders (SUD). Understanding what motivates substance use has been a focus of SUD research for decades. Much of this corpus of work has focused on the shared effects of each drug class to increase dopaminergic transmission within the central reward pathways of the brain, or the "reward center." However, the precise influence of each drug class on dopamine signaling, and the extent thereof, differs considerably. Furthermore, the aforementioned substances have effects on several neurobiological targets that mediate and modulate their addictive properties. The current manuscript sought to review the influence of drug class on the rewarding effects of each of the major pharmacological classes of addictive drugs (i.e., psychostimulants, opioids, nicotine, alcohol, and cannabinoids). Our review suggests that even subtle differences in drug effects can result in significant variability in the subjective experience of the drug, altering rewarding and other reinforcing effects. Additionally, this review will argue that reward (i.e., the attractive and motivational property of a stimulus) alone is not sufficient to explain the abuse liability of these substances. Instead, abuse potential is best examined as a function of both positive and negative reinforcing drug effects (i.e., stimuli that the subject will work to attain and stimuli that the subject will work to end or avoid, respectively). Though reward is central to drug use, the factors that motivate and maintain drug taking are varied and complex, with much to be elucidated.

Computational Mechanisms Underlying Multi-Step Planning Deficits in Methamphetamine Use Disorder

Current theories suggest individuals with methamphetamine use disorder (iMUDs) have difficulty considering long-term outcomes in decision-making, which could contribute to risk of relapse. Aversive interoceptive states (e.g., stress, withdrawal) are also known to increase this risk. The present study analyzed computational mechanisms of planning in iMUDs, and examined the potential impact of an aversive interoceptive state induction. A group of 40 iMUDs and 49 healthy participants completed two runs of a multi-step planning task, with and without an anxiogenic breathing resistance manipulation. Computational modeling revealed that iMUDs had selective difficulty identifying the best overall plan when this required enduring negative short-term outcomes - a mechanism referred to as aversive pruning. Increases in reported craving before and after the induction also predicted greater aversive pruning in iMUDs. These results highlight a novel mechanism that could promote poor choice in recovering iMUDs and create vulnerability to relapse.

A Cognitive Pathway to Persistent, Maladaptive Choice

BACKGROUND

Correctly recognising that alcohol or other substances are causing problems is a necessary condition for those problems to spur beneficial behaviour change. Yet such recognition is neither immediate nor straightforward. Recognition that one's alcohol or drug use is causing negative consequences often occurs gradually. Contemporary addiction neuroscience has yet to make progress in understanding and addressing these recognition barriers, despite evidence that a lack of problem recognition is a primary impediment to seeking treatment.

SUMMARY

Based on our recent empirical work, this article shows how recognition barriers can emerge from dual constraints on how we learn about the negative consequences of our actions. One constraint is imposed by the characteristics of negative consequences themselves. A second constraint is imposed by the characteristics of human cognition and information processing. In some people, the joint action of these constraints causes a lack of correct awareness of the consequences of their behaviour and reduced willingness to update that knowledge and behaviour when confronted with counterevidence.

KEY MESSAGES

This "cognitive pathway" can drive persistent, maladaptive choice.

How We Lost 90% of Participants on a Bad Bet: Results from a Pilot Randomized Controlled Trial on Cognitive Bias Modification in Problem Gamblers

Whilst opportunities to participate in gambling have increased, access to support for problem gamblers is lacking behind. This lack of balance calls for improved and accessible intervention methods. The present double-blind randomized controlled trial (RCT) explored the effectiveness of two interventions targeting automatic cognitive processes, known as Attentional Bias Modification (AtBM) and Approach Bias Modification (ApBM). It was hypothesized these interventions would reduce gambling behavior and reduce or reverse targeted biases. Participants (N = 331) were community-recruited Flemish (35%) and Dutch (65%) adult problem gamblers motivated to reduce or stop their gambling who received either six sessions of active training (AtBM or ApBM) or of the corresponding sham-training (sham-AtBM or sham-ApBM). Due to high attrition rates (90.1% up to the intervention phase) the study was terminated before completion, since it would greatly limit the validity of any results. A post hoc qualitative study was performed on a subset of participants to gain insight into contributing factors for the high attrition rate. Issues negatively impacting participants' motivation to complete the program were identified, as well as elements of the program that received approval. The results from this study provide a first insight into the potential of the use of online cognitive bias modification (CBM) interventions in problem gambling (PG). Suggestions and directions for future studies are discussed.

Punishment resistance for cocaine is associated with inflexible habits in rats

Addiction is characterized by continued drug use despite negative consequences. In an animal model, a subset of rats continues to self-administer cocaine despite footshock consequences, showing punishment resistance. We sought to test the hypothesis that punishment resistance arises from failure to exert goal-directed control over habitual cocaine seeking. While habits are not inherently permanent or maladaptive, continued use of habits under conditions that should encourage goal-directed control makes them maladaptive and inflexible. We trained male and female Sprague Dawley rats on a seeking-taking chained schedule of cocaine self-administration. We then exposed them to four days of punishment testing in which footshock was delivered randomly on one-third of trials. Before and after punishment testing (four days pre-punishment and ≥ four days post-punishment), we assessed whether cocaine seeking was goal-directed or habitual using outcome devaluation via cocaine satiety. We found that punishment resistance was associated with continued use of habits, whereas punishment sensitivity was associated with increased goal-directed control. Although punishment resistance for cocaine was not predicted by habitual responding pre-punishment, it was associated with habitual responding post-punishment. In parallel studies of food self-administration, we similarly observed that punishment resistance was associated with habitual responding post-punishment but not pre-punishment in males, although it was associated with habitual responding both pre- and post-punishment in females, indicating that punishment resistance was predicted by habitual responding in food-seeking females. These findings indicate that punishment resistance is related to habits that have become inflexible and persist under conditions that should encourage a transition to goal-directed behavior.

Age moderates the association of optimism on craving during substance use disorder treatment

BACKGROUND

Optimism, characterized by a positive expectancy toward future outcomes, has garnered attention for its potential role in influencing well-being and may be a protective factor in substance use disorder (SUD) treatment. This study evaluated the relationship of optimism and craving among those in substance use disorder SUD treatment.

METHODS

Drawing from a cohort of 4201 individuals in residential SUD treatment programs, this study used both cross-sectional and longitudinal assessment to examine tonic (steady-state) and cue-induced (phasic) cravings across individuals primarily using eight classes of substances. Previous research established that optimism increases during adulthood and peaks during an individual's 50s. This study sought to establish if the association between optimism and craving is moderated by age during the first week of treatment and if that relationship changes over the course of treatment both within and between-person.

RESULTS

This study found a negative correlation between optimism and craving intensity. Elevated optimism scores correlated with substantially reduced levels of both tonic (β = -0.31, p < 0.001) and cue-induced (β = -0.29, p < 0.001) cravings. Age was a significant moderator of the relationship between optimism and craving such that as individuals age, the potency of optimism in mitigating cravings gradually attenuates (interaction for tonic craving: β = 0.06, p < 0.001; interaction for cue-induced craving: β = 0.05, p < 0.001). Reflected in the fact that in older individuals' cravings tended to converge toward lower or moderate levels, regardless of their optimism scores.

CONCLUSIONS

By delineating the contemporaneous association between high optimism and lower cravings, the study suggests that interventions aimed at fostering optimism may represent an avenue to improve the effectiveness of SUD treatment, especially in emerging adults.

The small G-protein Rac1 in the dorsomedial striatum promotes alcohol-dependent structural plasticity and goal-directed learning in mice

The small G-protein Rac1 promotes the formation of filamentous actin (F-Actin). Actin is a major component of dendritic spines, and we previously found that alcohol alters actin composition and dendritic spine structure in the nucleus accumbens (NAc) and the dorsomedial striatum (DMS). To examine if Rac1 contributes to these alcohol-mediated adaptations, we measured the level of GTP-bound active Rac1 in the striatum of mice following 7 weeks of intermittent access to 20% alcohol. We found that chronic alcohol intake activates Rac1 in the DMS of male mice. In contrast, Rac1 is not activated by alcohol in the NAc and DLS of male mice, or in the DMS of female mice. Similarly, closely related small G-proteins are not activated by alcohol in the DMS, and Rac1 activity is not increased in the DMS by moderate alcohol or natural reward. To determine the consequences of alcohol-dependent Rac1 activation in the DMS of male mice, we inhibited endogenous Rac1 by infecting the DMS of mice with an AAV expressing a dominant negative form of the small G-protein (Rac1-DN). We found that overexpression of AAV-Rac1-DN in the DMS inhibits alcohol-mediated Rac1 signaling and attenuates alcohol-mediated F-actin polymerization, which corresponded with a decrease in dendritic arborization and spine maturation. Finally, we provide evidence to suggest that Rac1 in the DMS plays a role in alcohol-associated goal-directed learning. Together, our data suggest that Rac1 in the DMS plays an important role in alcohol-dependent structural plasticity and aberrant learning.

Significance Statement

Addiction, including alcohol use disorder, is characterized by molecular and cellular adaptations that promote maladaptive behaviors. We found that Rac1 was activated by alcohol in the dorsomedial striatum (DMS) of male mice. We show that alcohol-mediated Rac1 signaling is responsible for alterations in actin dynamics and neuronal morphology. We also present data to suggest that Rac1 is important for alcohol-associated learning processes. These results suggest that Rac1 in the DMS is an important contributor to adaptations that promote alcohol use disorder.

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.

Leucine-rich repeat kinase 2 limits dopamine D1 receptor signaling in striatum and biases against heavy persistent alcohol drinking

The transition from hedonic alcohol drinking to problematic drinking is a hallmark of alcohol use disorder that occurs only in a subset of drinkers. This transition requires long-lasting changes in the synaptic drive and the activity of striatal neurons expressing dopamine D1 receptor (D1R). The molecular mechanisms that generate vulnerability in some individuals to undergo the transition are less understood. Here, we report that the Parkinson's-related protein leucine-rich repeat kinase 2 (LRRK2) modulates striatal D1R function to affect the behavioral response to alcohol and the likelihood that mice transition to heavy, persistent alcohol drinking. Constitutive deletion of the Lrrk2 gene specifically from D1R-expressing neurons potentiated D1R signaling at the cellular and synaptic level and enhanced alcohol-related behaviors and drinking. Mice with cell-specific deletion of Lrrk2 were more prone to heavy alcohol drinking, and consumption was insensitive to punishment. These findings identify a potential novel role for LRRK2 function in the striatum in promoting resilience against heavy and persistent alcohol drinking.

Self-Forgiveness and Self-Condemnation in the Context of Addictive Behavior and Suicidal Behavior

Addictive behavior and suicidal behavior are serious individual- and public-level health concerns. For those struggling with either or both, self-condemnation is a common experience, especially with respect to shame, guilt, and self-stigma. Self-forgiveness, a construct common to both religiousness/spirituality and positive psychology, may be an effective tool in addressing the self-condemnation inherent to those struggling with addictive behavior and suicidal behavior. In this review paper, we discuss (1) the nature and definition of forgiveness, (2) theoretical modeling developed regarding the general association of forgiveness with health, (3) theoretical modeling developed regarding the specific association of forgiveness with better outcomes related to addictive and/or suicidal behavior, (4) the relevance of shame, guilt, and self-stigma to the development and maintenance of addictive and suicidal behavior, and (5) the role of self-forgiveness in addressing self-condemnation, especially shame, guilt, and self-stigma. Little work explicitly focused on the association of self-forgiveness with shame, guilt, and/or self-stigma has been done. However, empirical evidence is accumulating in support of other associations proposed in the Forgiveness-Addiction-Recovery Association (FARA) Model described herein. As such, it is likely that similar support will be found when the focus is deliberately turned to shame, guilt, and self-stigma.

Reward, relief, and habit drinking profiles in treatment seeking individuals with an AUD

AIMS

This study aimed to compare reward, relief, and habit treatment-seeking individuals on recent drinking, alcohol use disorder (AUD) phenomenology, and mood. The second aim of the study was to evaluate the predictive validity of reward, relief, and habit profiles.

METHOD

Treatment-seeking individuals with an AUD (n = 169) were recruited to participate in a medication trial for AUD (NCT03594435). Reward, relief, and habit drinking groups were assessed using the UCLA Reward Relief Habit Drinking Scale. Group differences at baseline were evaluated using univariate analyses of variance. A subset of participants were enrolled in a 12-week, double-blind, placebo-controlled medication trial (n = 102), and provided longitudinal drinking and phenomenology data. The predictive validity of group membership was assessed using linear regression analyses.

RESULTS

At baseline, individuals who drink primarily for relief had higher craving and negative mood than those who drink for reward and habit. Prospectively, membership in the relief drinking group predicted greater alcohol use, greater heavy drinking, and fewer days abstinent compared to those in the reward drinking group. Membership in the relief drinking group also predicted greater alcohol craving, more alcohol-related consequences, and more anxiety symptoms over 12 weeks compared to those in the reward drinking group.

CONCLUSIONS

This study provides support for reward and relief drinking motive profiles in treatment-seeking individuals with an AUD. Membership in the relief drinking motive group was predictive of poorer drinking outcomes and more negative symptomology over 12 weeks, indicating that individuals who drink for relief may be a particularly vulnerable sub-population of individuals with AUD.

The utility of a latent-cause framework for understanding addiction phenomena

Computational models of addiction often rely on a model-free reinforcement learning (RL) formulation, owing to the close associations between model-free RL, habitual behavior and the dopaminergic system. However, such formulations typically do not capture key recurrent features of addiction phenomena such as craving and relapse. Moreover, they cannot account for goal-directed aspects of addiction that necessitate contrasting, model-based formulations. Here we synthesize a growing body of evidence and propose that a latent-cause framework can help unify our understanding of several recurrent phenomena in addiction, by viewing them as the inferred return of previous, persistent "latent causes". We demonstrate that applying this framework to Pavlovian and instrumental settings can help account for defining features of craving and relapse such as outcome-specificity, generalization, and cyclical dynamics. Finally, we argue that this framework can bridge model-free and model-based formulations, and account for individual variability in phenomenology by accommodating the memories, beliefs, and goals of those living with addiction, motivating a centering of the individual, subjective experience of addiction and recovery.

Ultra-Brief Breath Counting (Mindfulness) Training Abolishes Negative Affect-Induced Alcohol Motivation in Hazardous Community Drinkers

Objectives

Mindfulness therapy improves drinking outcomes arguably by attenuating negative mood-induced drinking, but this mechanism has not been demonstrated in hazardous community drinkers. To address this, three studies tested whether a key ingredient of mindfulness, breath counting, would attenuate the increase in motivation for alcohol produced by experimentally induced negative mood, in hazardous community drinkers.

Method

In three studies, hazardous community drinkers were randomized to receive either a 6-min breath counting training or listen to a recited extract from a popular science book, before all participants received a negative mood induction. Motivation for alcohol was measured before and after listening to either the breath counting training or the control audio files, with a craving questionnaire in two online studies (n = 122 and n = 111), or an alcohol versus food picture choice task in a pub context in one in-person study (n = 62).

Results

In Study 1, breath counting reduced alcohol craving. However, since the mood induction protocol did not increase craving, the effect of breath counting in reversing such increase could not be demonstrated. Online breath counting eliminated the increase in alcohol craving induced by negative mood (Study 2) and eliminated the stress-induced increase in alcohol picture choice in the pub environment (Study 3).

Conclusions

Briefly trained breath counting attenuated negative mood-induced alcohol motivation in hazardous community drinkers. These results suggest that breath counting is a reliable and practical method for reducing the impact of negative emotional triggers on alcohol motivation.

Preregistration

These studies are not preregistered.

Different mechanisms underlie compulsive alcohol self-administration in male and female rats

BACKGROUND

Sex is an important factor in the progression and treatment of alcohol addiction, and therapeutic approaches may have to be tailored to potential sex differences. This highlights the importance of understanding sex differences in behaviors that reflect key elements of clinical alcohol addiction, such as continued use despite negative consequences ("compulsive use"). Studies in experimental animals can help provide an understanding of the role sex plays to influence these behaviors.

METHODS

Large populations of genetically heterogeneous male and female Wistar rats were tested in an established model of compulsive alcohol self-administration, operationalized as alcohol responding despite contingent foot shock punishment. We also tested baseline (fixed ratio, unpunished) operant alcohol self-administration, motivation to self-administer alcohol (progressive ratio), and temporal discounting for alcohol reward. In search of predictors of compulsivity, animals were screened for novelty-induced place preference, anxiety-like behavior, pain sensitivity and corticosterone levels. The estrous cycle was monitored throughout the study.

RESULTS

Unpunished self-administration of alcohol did not differ between males and females when alcohol intake was corrected for body weight. Overall, females showed higher levels of compulsive responding for alcohol. Compulsive response rates showed bimodal distributions in male but not in female rats when intermediate shock intensities were used (0.2 and 0.25 mA); at higher shock intensities, responding was uniformly suppressed in both males and females. We also found less steep discounting in females when alcohol was devalued by delaying its delivery. Males exhibited a stronger motivation to obtain alcohol under unpunished conditions, while females showed higher corticosterone levels at baseline. Factor analysis showed that an underlying dimension related to stress and pain predicted compulsivity in females, while compulsivity in males was predicted by a reward factor. We did not find differences in alcohol-related behaviors throughout the various stages of the estrous cycle.

CONCLUSIONS

Our results suggest that mechanisms promoting compulsivity, a key feature of alcohol addiction, likely differ between males and females. This underscores the importance of considering sex as a biological variable in both preclinical and clinical research, and has potential treatment implications in alcohol addiction.

Levonorgestrel maintains goal-directed behavior in habit-trained intact female rats

Hormonal contraceptives are utilized by millions of women worldwide. However, it remains unclear if these powerful endocrine modulators may alter cognitive function. Habit formation involves the progression of instrumental learning as it goes from being a conscious goal-directed process to a cue-driven automatic habitual motor response. Dysregulated goal and/or habit is implicated in numerous psychopathologies, underscoring the relevance of examining the effect of hormonal contraceptives on goal-directed and habitual behavior. This study examined the effect of levonorgestrel (LNG), a widely used progestin-type contraceptive, on the development of habit in intact female rats. Rats were implanted with subcutaneous capsules that slowly released LNG over the course of the experiment or cholesterol-filled capsules. All female rats underwent operant training followed by reward devaluation to test for habit. One group of females was trained at a level that is sub-threshold to habit, while another group of females was trained to a level well over the habit threshold observed in intact females. The results reveal that all sub-threshold trained rats remained goal-directed irrespective of LGN treatment, suggesting LNG is not advancing habit formation in female rats at this level of reinforcement. However, in rats that were overtrained well above the threshold, cholesterol females showed habitual behavior, thus replicating a portion of our original studies. In contrast, LNG-treated habit-trained rats remained goal-directed, indicating that LNG impedes the development and/or expression of habit following this level of supra-threshold to habit training. Thus, LNG may offset habit formation by sustaining attentional or motivational processes during learning in intact female rats. These results may be clinically relevant to women using this type of hormonal contraceptive as well as in other progestin-based hormone therapies.

Habit and persistence

Voluntary behaviors (operants) can come in two varieties: Goal-directed actions, which are emitted based on the remembered value of the reinforcer, and habits, which are evoked by antecedent cues and performed without the reinforcer's value in active memory. The two are perhaps most clearly distinguished with the reinforcer-devaluation test: Goal-directed actions are suppressed when the reinforcer is separately devalued and responding is tested in extinction, and habitual behaviors are not. But what is the function of habit learning? Habits are often thought to be strong and unusually persistent. The present selective review examines this idea by asking whether habits identified by the reinforcer-devaluation test are more resistant to extinction, resistant to the effects of other contingency change, vulnerable to relapse, resistant to the weakening effects of context change, or permanently in place once they are learned. Surprisingly little evidence supports the idea that habits are permanent or more persistent. Habits are more context-specific than goal-directed actions are. Methods that make behavior persistent do not necessarily work by encouraging habit. The function of habit learning may not be to make a behavior strong or more persistent but to make it automatic and efficient in a particular context.

Making and breaking habits: Revisiting the definitions and behavioral factors that influence habits in animals

Habits have garnered significant interest in studies of associative learning and maladaptive behavior. However, habit research has faced scrutiny and challenges related to the definitions and methods. Differences in the conceptualizations of habits between animal and human studies create difficulties for translational research. Here, we review the definitions and commonly used methods for studying habits in animals and humans and discuss potential alternative ways to assess habits, such as automaticity. To better understand habits, we then focus on the behavioral factors that have been shown to make or break habits in animals, as well as potential mechanisms underlying the influence of these factors. We discuss the evidence that habitual and goal-directed systems learn in parallel and that they seem to interact in competitive and cooperative manners. Finally, we draw parallels between habitual responding and compulsive drug seeking in animals to delineate the similarities and differences in these behaviors.

Positive correlation between measures of habitual responding and motivated responding in mice

Habit and motivation are thought to be separate processes, with motivated behavior often considered to be goal directed, whereas habits are defined by the absence of goal-directed control over behavior. However, there has been increasing interrogation of the binary nature of habitual versus goal-directed behavior. Furthermore, although drug and alcohol exposure can promote the formation of habits, drug seeking itself can also be highly flexible, pointing toward the need for complex consideration of the parallel processes that drive behavior. The goal of the current study was to determine whether there was a relation between motivation-as measured by progressive ratio-and habit-as measured by contingency degradation-and whether this relation was affected by ethanol exposure history and sex. The results showed that these measures were positively correlated such that greater contingency insensitivity was associated with achieving higher break points on the progressive-ratio task. However, this relation depended on reinforcement schedule history, ethanol exposure history, and sex. These point to potential relations between measures of habit and motivation and stress the importance of carefully parsing behavioral findings and assays. These findings are also expected to inform future substance use research, as drug history may affect these relations.

ABC-training as a new intervention for hazardous alcohol drinking: Two proof-of-principle randomized pilot studies

BACKGROUND AND AIMS

ABC-training is a new intervention to encourage health behavior change that targets the automatic activation of adaptive beliefs (i.e. automatic inferences). The aim of this proof-of-principle study was to test the effectiveness of web-based ABC-training to change outcome expectancies of alcohol drinking in a sample of hazardous drinkers.

DESIGN

One exploratory and one confirmatory experiment with two between-subject conditions (online ABC- and control-training) and assessments at baseline and 1 week later (after three sessions of training).

SETTING

Participants recruited on Prolific Academic completed the web-based study.

PARTICIPANTS

Adults with self-reported hazardous alcohol drinking (Experiment 1: 193 adults, United Kingdom, age mean = 46.7 years; Experiment 2: 282 adults, different nationalities, age mean = 38.3 years).

INTERVENTION AND COMPARATOR

ABC-training involved completing an online task that required choosing personally relevant alternative behaviors to drinking alcohol in personally relevant antecedent contexts to attain personally important outcomes. Comparator was control-training, in which participants selected both the alternative behaviors and alcohol drinking an equal number of times. Training was completed at baseline, after 3 days and after 1 week.

MEASUREMENTS

Primary outcome was change in automatic and self-reported (negative/positive) outcome expectancies of alcohol drinking from baseline to after 1 week. Secondary outcomes were change in weekly alcohol consumption, self-efficacy, craving and motivation (and approach-alcohol associations in Experiment 1). Moderators were baseline outcome scores, motivation, age and alcohol dependency.

FINDINGS

Findings of this study are as follows: stronger increase in negative outcome expectancies after ABC- than control-training (Experiment 1: self-report, 95% confidence interval of difference scores (CIdiff ) = [0.04, Inf]; automatic, CIdiff  = [0.01, Inf]; Experiment 2: self-report, CIdiff  = [0.16, Inf]; automatic, CIdiff  = [0.002, Inf]). Stronger reduction in self-reported positive outcome expectancies after ABC- than control-training (Experiment 1: CIdiff  = [-Inf, -0.01]; Experiment 2: CIdiff  = [-Inf, -0.21]) but mixed findings on automatic positive outcome expectancies (Experiment 1: CIdiff  = [-Inf, 0.02]; Experiment 2: CIdiff  = [-Inf, -0.001]).

CONCLUSIONS

ABC-training may change outcome expectancies of alcohol consumption, but testing of clinically relevant effects in other samples is warranted.

The Willpower Paradox: Possible and Impossible Conceptions of Self-Control

Self-control denotes the ability to override current desires to render behavior consistent with long-term goals. A key assumption is that self-control is required when short-term desires are transiently stronger (more preferred) than long-term goals and people would yield to temptation without exerting self-control. We argue that this widely shared conception of self-control raises a fundamental yet rarely discussed conceptual paradox: How is it possible that a person most strongly desires to perform a behavior (e.g., eat chocolate) and at the same time desires to recruit self-control to prevent themselves from doing it? A detailed analysis reveals that three common assumptions about self-control cannot be true simultaneously. To avoid the paradox, any coherent theory of self-control must abandon either the assumption (a) that recruitment of self-control is an intentional process, or (b) that humans are unitary agents, or (c) that self-control consists in overriding the currently strongest desire. We propose a taxonomy of different kinds of self-control processes that helps organize current theories according to which of these assumptions they abandon. We conclude by outlining unresolved questions and future research perspectives raised by different conceptions of self-control and discuss implications for the question of whether self-control can be considered rational.

Effects of early-life stress on probabilistic reversal learning and response perseverance in young adults

Early life stress (ELS), including experiences with abuse and neglect, are related to several negative health outcomes in adulthood. One area that has received attention is the increased rate of substance abuse disorder in individuals who had experienced ELS. Given the critical role habitual behavior in the development of substance abuse, ELS may affect the trajectory of neural development such that habitual responding is more dominant than in individuals who did not experience ELS. Here, we examine learning of a probabilistic classification task (the Weather Prediction Task) in healthy young adults who reported significant ELS and those that did not. This task can be learned in a declarative, model-based manner, or in a more habitual, stimulus-response manner. Participants learned to choose the outcome (sun or rain) that was probabilistically associated with each cue combination through reinforcement on each trial. After 100 trials, the probabilities were reversed, and we conceptualized habitual behavior as perseverating responses based on the old probabilities. We also collected information about subjective socio-economic status (sSES), anxiety, depression, and substance use from participants. Using multiple regression, we found that our measure of habitual responding was correlated with reported alcohol use, suggesting that our measure of habit has validity for health behaviors. Furthermore, we found that some forms of early life stress led to greater response perseverance after contingencies were reversed. Overall, the results suggest that childhood adversity may contribute to the development of habit.

Examining specific and non-specific symptoms of the best-fitting posttraumatic stress disorder model in conflict-exposed adolescents

BACKGROUND

The 5th revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) construes PTSD symptoms into 4 clusters (intrusion, avoidance, negative alterations in cognitions and mood, alterations in arousal and reactivity; Model 1). However, recent literature has shown that this symptom structure does not best represent PTSD. Unfortunately, the findings of studies investigating the proposed alternative models are from consensus. Adding to the complexity of the issue of symptom-grouping models is the identification of specific and non-specific symptoms of PTSD. The present study aims to address these gaps by identifying the best-fitting PTSD model and subsequently examining what symptoms are considered specific and non-specific to PTSD in adolescent-survivors of armed political conflict and violence.

METHODS

The study utilized a sample of 641 adolescent victim survivors. We conducted CFA analyses and compared nested models through the scaled χ2 difference test, while comparison of non-nested models was done using the Bayesian information criterion (BIC). The best-fitted model was used in the consequent analysis, where we statistically controlled for the effect of non-specific psychological distress on PTSD by comparing the factor loadings and factor correlations before and after accounting for distress using the Aroian z-test.

RESULTS

The results provide support for the 7-factor hybrid model of PTSD over other proposed models for the current sample. Moreover, the data reveal that only 7 items could be construed as core symptoms, while the rest of the symptoms can be considered non-PTSD specific.

CONCLUSIONS

Overall, the findings provide support for the validity of the hybrid PTSD model among political conflict-exposed adolescents. The results also show that the DSM-5 PTSD has both specific and non-specific features in the present sample of conflict-exposed adolescents. This has potential implications for theory, practice, and treatment of the disorder.

Be more mindful: Targeting addictive responses by integrating mindfulness with cognitive bias modification or cue exposure interventions

This review provides an overview of the most prominent neurocognitive effects of cognitive bias modification (CBM), cue-exposure therapy and mindfulness interventions for targeting addictive responses. It highlights the key insights that have stemmed from cognitive neuroscience and brain imaging research and combines these with insights from behavioural science in building a conceptual model integrating mindfulness with response-focused CBM or cue-exposure interventions. This furthers our understanding of whether and how mindfulness strategies may i) facilitate or add to the induced response-focused effects decreasing cue-induced craving, and ii) further weaken the link between craving and addictive responses. Specifically, awareness/monitoring may facilitate, and decentering may add to, response-focused effects. Combined awareness acceptance strategies may also diminish the craving-addiction link. The conceptual model presented in this review provides a specific theoretical framework to deepen our understanding of how mindfulness strategies and CBM or cue-exposure interventions can be combined to greatest effect. This is important in both suggesting a roadmap for future research, and for the further development of clinical interventions.

Modulation of cue value and the augmentation of heroin seeking in chronically food-restricted male rats under withdrawal

Food restriction augments drug seeking in abstinent rats. The underlying motivational mechanisms, however, remain unclear. We hypothesized that caloric restriction enhances the incentive value attributed to drug-associated cues and, in turn, augments drug seeking. Male rats were trained to lever-press for heroin, and then moved to the animal colony for a forced-abstinence period. Rats were maintained on free access to food (Sated) or subjected to 14 days of food restriction (FDR). In a series of experiments, we assessed the effect of food-restriction on the incentive value of heroin-associated cues. Tests included performance under a progressive ratio (PR) schedule of reinforcement maintained by heroin-associated cues, acquisition of a novel operant response reinforced by drug-associated cues, effect of food-restriction on operant response reinforced by neutral cues, acquisition of a novel operant response reinforced by drug-associated or neutral cues, and the effect of food-restriction on operant response reinforced by drug-associated or neutral cues, under a discrete choice procedure. Food-restriction did not change breakpoints in PR maintained by heroin-associated cues. FDR rats acquired the novel response at a greater level compared to the Sated group. Food-restriction-induced increase in novel-response rate was observed for both heroin-paired and the neutral cue. Responding for a heroin-associated cue was greater than for the neutral cue in both Sated and FDR groups. Response rate for the neutral cue, however, was greater in the FDR versus Sated group. Our findings suggest that food restriction increases the conditioned motivational properties of environmental stimuli, including, but not exclusive to, heroin-paired cues.

Interoception, alexithymia, and anxiety among individuals with alcohol use disorder

Background

Interoception (i.e., the ability to recognize bodily signals), alexithymia (i.e., the inability to recognize emotional states) and negative affect (i.e., unpleasant feelings such as anxiety) have been associated with alcohol use disorder (AUD). Previous research suggests that interoception may underlie alexithymia, which in turn may be associated with negative affectivity. However, this remains to be empirically tested. This study investigates whether alexithymia mediates the association between interoception and anxiety and whether this association differs across individuals with AUD and a healthy control (HC) comparison group.

Methods

The AUD group consisted of 99 participants enrolled in an 8-week abstinence-based inpatient treatment program. The HC group included 103 healthy individuals. The heartbeat counting task (HCT) was used to assess interoception (cardiac interoceptive accuracy). The Toronto Alexithymia Scale (TAS-20) was used to assess alexithymia. The Brief Symptom Inventory (BSI) was used to assess anxiety.

Results

The moderated mediation model with interoception as the predictor, alexithymia as the mediator, and negative affect (i.e., state anxiety) as the dependent variable was tested. The analysis showed that the conditional indirect effect of interoception on anxiety via alexithymia was significant for individuals with AUD [ab = -0.300, bootstrap 95% CI = (-0.618, -0.088)], as well as for HCs [ab = -0.088, bootstrap 95% CI = (-0.195, -0.014)]; however, the conditional indirect effect significantly differed across HCs and individuals with AUD. Namely, the mediated effect was greater among individuals with AUD compared to the HC group.

Conclusion

The results suggests that interoceptive impairment contributes to greater negative affect (i.e., state anxiety) via alexithymia especially for individuals with AUD. Improving emotion recognition via therapeutic methods focused on strengthening interoceptive abilities could improve outcomes for individuals receiving treatment for AUD.

Differential effects of acute and prolonged morphine withdrawal on motivational and goal-directed control over reward-seeking behavior

Opioid addiction is a relapsing disorder marked by uncontrolled drug use and reduced interest in normally rewarding activities. The current study investigated the impact of spontaneous withdrawal from chronic morphine exposure on emotional, motivational, and cognitive processes involved in regulating the pursuit and consumption of natural food rewards in male rats. In Experiment 1, rats experiencing acute morphine withdrawal lost weight and displayed somatic signs of drug dependence. However, hedonically-driven sucrose consumption was significantly elevated, suggesting intact and potentially heightened emotional reward processing. In Experiment 2, rats undergoing acute morphine withdrawal displayed reduced motivation when performing an effortful response for palatable food reward. Subsequent reward devaluation testing revealed that acute withdrawal also disrupted their ability to exert flexible goal-directed control over their reward-seeking behavior. Specifically, morphine-withdrawn rats displayed insensitivity to reward devaluation both when relying on prior action-outcome learning and when given direct feedback about the consequences of their actions. In Experiment 3, rats tested after prolonged morphine withdrawal displayed heightened rather than diminished motivation for food rewards and retained their ability to engage in flexible goal-directed action selection. However, brief re-exposure to morphine was sufficient to impair motivation and disrupt goal-directed action selection, though in this case insensitivity to reward devaluation was only observed in the presence of morphine-paired context cues and in the absence of response-contingent feedback. We suggest that these opioid-withdrawal induced deficits in motivation and goal-directed control may contribute to addiction by interfering with the pursuit of adaptive alternatives to drug use.

Conflicting theories on addiction aetiology and the strengths and limitations of substance use disorder disease modelling

A lack of cross-disciplinary unanimity prevails within addiction research. Theories conceptualizing addiction through the three-stage brain disease model contest other theories that substance use disorder is of behavioural or genetic origin. The reverberations of this lack of consensus are noticeable throughout addiction research and within the foundations of disease modelling. The availability of methods to investigate substance use disorder are inconsistent and sometimes unrepresentative. This review discusses theories of addiction aetiology, available models for addiction research and the strengths and limitations of current practical experimental methods of study.

Dysfunctional decision-making in binge-eating disorder: A meta-analysis and systematic review

Binge-Eating Disorder (BED) involves anticipatory craving and urges, subjective loss-of-control during binge-eating episodes, and post-feeding psychological distress and guilt. Evidence indicates neurocognitive dysfunctions contribute to BED onset, maintenance, and treatment response. However, an integrated understanding of how cognitive processes underpin BED symptomology is lacking. We utilised a multi-stage decision-making model defining ten cognitive processes underpinning Preference Formation, Choice Implementation, Feedback Processing, and Flexibility/Shifting, to comprehensively review research published since 2013. We used preregistered PICOS criteria to assess 1966 articles identified from PubMed, PsycInfo, and Scopus database searches. This yielded 50 studies reporting behavioural cognitive tasks outcomes, comparing individuals with BED to controls with normal and higher weight. Meta-analyses revealed a unique profile of cognitive dysfunctions that spanned all decision-making stages. Significant deficits were evident in Uncertainty Evaluation, Attentional Inhibition, Choice Consistency, and Cognitive Flexibility/Set-shifting. We propose a novel model of dysfunctional decision-making processes in BED and describe their role in binge-eating behaviour. We further highlight the potential for cognitive interventions to target these processes and address the significant treatment gap in BED.

Using lickometry to infer differential contributions of salience network regions during compulsion-like alcohol drinking

Alcohol use disorder extracts substantial personal, social and clinical costs, and continued intake despite negative consequences (compulsion-like consumption) can contribute strongly. Here we discuss lickometry, a simple method where lick times are determined across a session, while analysis across many aspects of licking can offer important insights into underlying psychological and action strategies, including their brain mechanisms. We first describe studies implicating anterior insula (AIC) and dorsal medial prefrontal cortex (dMPF) in compulsion-like responding for alcohol, then review work suggesting that AIC/ventral frontal cortex versus dMPF regulate different aspects of behavior (oral control and overall response strategy, versus moment-to-moment action organization). We then detail our lickometer work comparing alcohol-only drinking (AOD) and compulsion-like drinking under moderate- or higher-challenge (ModChD or HiChD, using quinine-alcohol). Many studies have suggested utilization of one of two main strategies, with higher motivation indicated by more bouts, and greater palatability suggested by longer, faster bouts. Instead, ModChD shows decreased variability in many lick measures, which is unexpected but consistent with the suggested importance of automaticity for addiction. Also surprising is that HiChD retains several behavior changes seen with ModChD, reduced tongue variability and earlier bout start, even though intake is otherwise disrupted. Since AIC-related measures are retained under both moderate- and higher-challenge, we propose a novel hypothesis that AIC sustains overall commitment regardless of challenge level, while disordered licking during HiChD mirrors the effects of dMPF inhibition. Thus, while AIC provides overall drive despite challenge, the ability to act is ultimately determined within the dMPF.

Chronic alcohol exposure alters action control via hyperactive premotor corticostriatal activity

Alcohol use disorder (AUD) alters decision-making control over actions, but disruptions to the responsible neural circuit mechanisms are unclear. Premotor corticostriatal circuits are implicated in balancing goal-directed and habitual control over actions and show disruption in disorders with compulsive, inflexible behaviors, including AUD. However, whether there is a causal link between disrupted premotor activity and altered action control is unknown. Here, we find that mice chronically exposed to alcohol (chronic intermittent ethanol [CIE]) showed impaired ability to use recent action information to guide subsequent actions. Prior CIE exposure resulted in aberrant increases in the calcium activity of premotor cortex (M2) neurons that project to the dorsal medial striatum (M2-DMS) during action control. Chemogenetic reduction of this CIE-induced hyperactivity in M2-DMS neurons rescued goal-directed action control. This suggests a direct, causal relationship between chronic alcohol disruption to premotor circuits and decision-making strategy and provides mechanistic support for targeting activity of human premotor regions as a potential treatment in AUD.

Opioid withdrawal: role in addiction and neural mechanisms

Withdrawal from opioids involves a negative affective state that promotes maintenance of drug-seeking behavior and relapse. As such, understanding the neurobiological mechanisms underlying withdrawal from opioid drugs is critical as scientists and clinicians seek to develop new treatments and therapies. In this review, we focus on the neural systems known to mediate the affective and somatic signs and symptoms of opioid withdrawal, including the mesolimbic dopaminergic system, basolateral amygdala, extended amygdala, and brain and hormonal stress systems. Evidence from preclinical studies suggests that these systems are altered following opioid exposure and that these changes mediate behavioral signs of negative affect such as aversion and anxiety during withdrawal. Adaptations in these systems also parallel the behavioral and psychological features of opioid use disorder (OUD), highlighting the important role of withdrawal in the development of addictive behavior. Implications for relapse and treatment are discussed as well as promising avenues for future research, with the hope of promoting continued progress toward characterizing neural contributors to opioid withdrawal and compulsive opioid use.

Reasons to Remain Critical About the Literature on Habits: A Commentary on Wood et al. (2022)

Wood et al. (2022) reviewed arguments in support of the idea that much of human behavior is habitual. In this commentary, we first point at ambiguities in the way Wood et al. referred to habits. This allows us to clarify the question that lies at the core of the debate on habits: To what extent is habitual behavior mediated by stimulus-response associations or by goal representations? We then argue that Wood et al. dismissed goal-directed explanations of habitual behavior too easily. Finally, we point out that Wood et al.'s reanalysis of our data is misleading in that a more fine-grained analysis supports rather than questions goal-directed accounts.

Self-management with alcohol over lifespan: psychological mechanisms, neurobiological underpinnings, and risk assessment

Self-management includes all behavioural measures and cognitive activities aimed at coping with challenges arising throughout the lifespan. While virtually all of these challenges can be met without pharmacological means, alcohol consumption has long been instrumentalized as a supporting tool to help coping with problems arising selectively at adolescence, adulthood, and ageing. Here, we present, to our knowledge, the first systematic review of alcohol instrumentalization throughout lifespan. We searched MEDLINE, Google Scholar, PsycINFO and CINAHL (from Jan, 1990, to Dec, 2022) and analysed consumption patterns, goals and potential neurobiological mechanisms. Evidence shows a regular non-addictive use of alcohol to self-manage developmental issues during adolescence, adulthood, and ageing. Alcohol is selectively used to overcome problems arising from dysfunctional personality traits, which manifest in adolescence. A large range of psychiatric disorders gives rise to alcohol use for the self-management of distinct symptoms starting mainly in adulthood. We identify those neuropharmacological effects of alcohol that selectively serve self-management under specific conditions. Finally, we discuss the adverse effects and associated risks that arise from the use of alcohol for self-management. Even well-controlled alcohol use adversely impacts health. Based on these findings, we suggest the implementation of an entirely new view. Health policy action may actively embrace both sides of the phenomenon through a personalized informed use that allows for harm-controlled self-management with alcohol.

Astrocyte activities in the external globus pallidus regulate action-selection strategies in reward-seeking behaviors

An imbalance in goal-directed and habitual behavioral control is a hallmark of decision-making-related disorders, including addiction. Although external globus pallidus (GPe) is critical for action selection, which harbors enriched astrocytes, the role of GPe astrocytes involved in action-selection strategies remained unknown. Using in vivo calcium signaling with fiber photometry, we found substantially attenuated GPe astrocytic activity during habitual learning compared to goal-directed learning. The support vector machine analysis predicted the behavioral outcomes. Chemogenetic activation of the astrocytes or inhibition of GPe pan-neuronal activities facilitates the transition from habit to goal-directed reward-seeking behavior. Next, we found increased astrocyte-specific GABA (γ-aminobutyric acid) transporter type 3 (GAT3) messenger RNA expression during habit learning. Notably, the pharmacological inhibition of GAT3 occluded astrocyte activation-induced transition from habitual to goal-directed behavior. On the other hand, attentional stimuli shifted the habit to goal-directed behaviors. Our findings suggest that the GPe astrocytes regulate the action selection strategy and behavioral flexibility.

Punishment resistance for cocaine is associated with inflexible habits in rats

Addiction is characterized by continued drug use despite negative consequences. In an animal model, a subset of rats continues to self-administer cocaine despite footshock consequences, showing punishment resistance. We sought to test the hypothesis that punishment resistance arises from failure to exert goal-directed control over habitual cocaine seeking. While habits are not inherently permanent or maladaptive, continued use of habits under conditions that should encourage goal-directed control makes them maladaptive and inflexible. We trained male and female Sprague Dawley rats on a seeking-taking chained schedule of cocaine self-administration (2 h/day). We then exposed them to 4 days of punishment testing, in which footshock (0.4 mA, 0.3 s) was delivered randomly on one-third of trials, immediately following completion of seeking and prior to extension of the taking lever. Before and after punishment testing (4 days pre-punishment and ≥4 days post-punishment), we assessed whether cocaine seeking was goal-directed or habitual using outcome devaluation via cocaine satiety. We found that punishment resistance was associated with continued use of habits, whereas punishment sensitivity was associated with increased goal-directed control. Although punishment resistance was not predicted by habitual responding pre-punishment, it was associated with habitual responding post-punishment. In parallel studies of food self-administration, we similarly observed that punishment resistance was associated with habitual responding post-punishment but not pre-punishment. These findings indicate that punishment resistance is related to habits that have become inflexible and persist under conditions that should encourage a transition to goal-directed behavior.

Pathways to the persistence of drug use despite its adverse consequences

The persistence of drug taking despite its adverse consequences plays a central role in the presentation, diagnosis, and impacts of addiction. Eventual recognition and appraisal of these adverse consequences is central to decisions to reduce or cease use. However, the most appropriate ways of conceptualizing persistence in the face of adverse consequences remain unclear. Here we review evidence that there are at least three pathways to persistent use despite the negative consequences of that use. A cognitive pathway for recognition of adverse consequences, a motivational pathway for valuation of these consequences, and a behavioral pathway for responding to these adverse consequences. These pathways are dynamic, not linear, with multiple possible trajectories between them, and each is sufficient to produce persistence. We describe these pathways, their characteristics, brain cellular and circuit substrates, and we highlight their relevance to different pathways to self- and treatment-guided behavior change.