Relatively strong automatic appetitive action-tendencies in male carriers of the OPRM1 G-allele

Approach-bias predicts development of cannabis problem severity in heavy cannabis users: results from a prospective FMRI study

A potentially powerful predictor for the course of drug (ab)use is the approach-bias, that is, the pre-reflective tendency to approach rather than avoid drug-related stimuli. Here we investigated the neural underpinnings of cannabis approach and avoidance tendencies. By elucidating the predictive power of neural approach-bias activations for future cannabis use and problem severity, we aimed at identifying new intervention targets. Using functional Magnetic Resonance Imaging (fMRI), neural approach-bias activations were measured with a Stimulus Response Compatibility task (SRC) and compared between 33 heavy cannabis users and 36 matched controls. In addition, associations were examined between approach-bias activations and cannabis use and problem severity at baseline and at six-month follow-up. Approach-bias activations did not differ between heavy cannabis users and controls. However, within the group of heavy cannabis users, a positive relation was observed between total lifetime cannabis use and approach-bias activations in various fronto-limbic areas. Moreover, approach-bias activations in the dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) independently predicted cannabis problem severity after six months over and beyond session-induced subjective measures of craving. Higher DLPFC/ACC activity during cannabis approach trials, but lower activity during cannabis avoidance trials were associated with decreases in cannabis problem severity. These findings suggest that cannabis users with deficient control over cannabis action tendencies are more likely to develop cannabis related problems. Moreover, the balance between cannabis approach and avoidance responses in the DLPFC and ACC may help identify individuals at-risk for cannabis use disorders and may be new targets for prevention and treatment.

Testing multiple levels of influence in the intergenerational transmission of alcohol disorders from a developmental perspective: the example of alcohol use promoting peers and μ-opioid receptor M1 variation

This study examined the interplay between the influence of peers who promote alcohol use and μ-opioid receptor M1 (OPRM1) genetic variation in the intergenerational transmission of alcohol use disorder (AUD) symptoms while separating the "traitlike" components of AUD symptoms from their age-specific manifestations at three ages from emerging adulthood (17-23 years) to adulthood (29-40 years). The results for males were consistent with genetically influenced peer selection mechanisms as mediators of parent alcoholism effects. Male children of alcoholics were less likely to be carriers of the G allele in single nucleotide polymorphism A118G (rs1799971), and those who were homozygous for the A allele were more likely to affiliate with alcohol use promoting peers who increased the risk for AUD symptoms at all ages. There was evidence for women of an interaction between OPRM1 variation and peer affiliations but only at the earliest age band. Peer influences had stronger effects among women who were G-carriers. These results illustrate the complex ways in which the interplay between influences at multiple levels of analysis can underlie the intergenerational transmission of alcohol disorders as well as the importance of considering age and gender differences in these pathways.

The moderating effect of alcohol-specific parental rule-setting on the relation between the dopamine D2 receptor gene (DRD2), the μ-opioid receptor gene (OPRM1) and alcohol use in young adolescents

AIMS

The main aim of the study was to test the moderating effect of two genetic polymorphisms, one in the dopamine D2 receptor gene (DRD2) and one in the mu-opioid receptor gene (OPRM1), on the link between parental rule-setting and adolescent alcohol use.

METHODS

A total of 214 adolescents (M(age )=13.7, 44.9% male) provided saliva samples and completed survey items describing alcohol use and parental rule-setting.

RESULTS

Findings indicated that alcohol-specific parental rule-setting was more robustly associated with alcohol use for adolescents with the DRD2 A1 risk allele and for those with the OPRM1 G-allele.

CONCLUSION

This study replicates the interaction between parental rule-setting and the DRD2 risk allele on adolescent alcohol use and extends the literature by demonstrating the moderating effects of the OPRM1 risk allele on the link between parental rule-setting and adolescent alcohol use.

Influence of the OPRM1 A118G polymorphism on alcohol-induced euphoria, risk for alcoholism and the clinical efficacy of naltrexone

Alcohol-use disorders are thought to be heterogeneous in etiology, pathophysiology and response to treatment. One hypothesized contributor to this variability is the common A118G polymorphism of the µ-opioid receptor gene, OPRM1. This article critically evaluates the evidence that the A118G substitution affects subjective, behavioral and neurobiological responses to alcohol and the opioid receptor antagonist, naltrexone. Although screening of patients in a clinical setting remains premature, results suggest the A118G substitution may influence one etiological pathway to alcoholism, for which naltrexone pharmacotherapy is more effective.

Quantifying individual variation in the propensity to attribute incentive salience to reward cues

If reward-associated cues acquire the properties of incentive stimuli they can come to powerfully control behavior, and potentially promote maladaptive behavior. Pavlovian incentive stimuli are defined as stimuli that have three fundamental properties: they are attractive, they are themselves desired, and they can spur instrumental actions. We have found, however, that there is considerable individual variation in the extent to which animals attribute Pavlovian incentive motivational properties ("incentive salience") to reward cues. The purpose of this paper was to develop criteria for identifying and classifying individuals based on their propensity to attribute incentive salience to reward cues. To do this, we conducted a meta-analysis of a large sample of rats (N = 1,878) subjected to a classic Pavlovian conditioning procedure. We then used the propensity of animals to approach a cue predictive of reward (one index of the extent to which the cue was attributed with incentive salience), to characterize two behavioral phenotypes in this population: animals that approached the cue ("sign-trackers") vs. others that approached the location of reward delivery ("goal-trackers"). This variation in Pavlovian approach behavior predicted other behavioral indices of the propensity to attribute incentive salience to reward cues. Thus, the procedures reported here should be useful for making comparisons across studies and for assessing individual variation in incentive salience attribution in small samples of the population, or even for classifying single animals.

An imaging genetics approach to understanding social influence

Normative social influences shape nearly every aspect of our lives, yet the biological processes mediating the impact of these social influences on behavior remain incompletely understood. In this Hypothesis, we outline a theoretical framework and an integrative research approach to the study of social influences on the brain and genetic moderators of such effects. First, we review neuroimaging evidence linking social influence and conformity to the brain's reward system. We next review neuroimaging evidence linking social punishment (exclusion) to brain systems involved in the experience of pain, as well as evidence linking exclusion to conformity. We suggest that genetic variants that increase sensitivity to social cues may predispose individuals to be more sensitive to either social rewards or punishments (or potentially both), which in turn increases conformity and susceptibility to normative social influences more broadly. To this end, we review evidence for genetic moderators of neurochemical responses in the brain, and suggest ways in which genes and pharmacology may modulate sensitivity to social influences. We conclude by proposing an integrative imaging genetics approach to the study of brain mediators and genetic modulators of a variety of social influences on human attitudes, beliefs, and actions.

Behavioural approach tendencies to heroin-related stimuli in abstinent heroin abusers

RATIONALE

Drug-related cues can elicit approach responses in drug users. However, no relevant research has ever concerned heroin abusers. In the present study, we investigated whether the abstinent heroin abusers demonstrated special behavioural tendencies to approach or avoid the drug-related stimuli compared with neutral stimuli.

METHOD

Twenty-two male abstinent heroin abusers (AH) and 20 healthy males (NC) were tested by a Pull/Push Task. Participants pulled (approach response) or pushed (avoidance response) a lever in response to the content of stimulus pictures (i.e. heroin-related versus neutral). The approach and avoidance scores were therefore calculated based on response times and directions to reflect their behavioural tendencies.

RESULTS AND CONCLUSION

Relative to the NC individuals, the AH individuals demonstrated significantly heightened tendencies to approach ("pull") the heroin-related stimuli in comparison with the neutral stimuli, while their tendencies to avoid ("push") the heroin-related stimuli were marginally blunted, reflecting a special bias for AH individuals to behaviourally approach, and simultaneously resist to avoid, heroin-related cues.

Pilot study examining the frequency of several gene polymorphisms involved in morphine pharmacodynamics and pharmacokinetics in a morbidly obese population

Morbidly obese patients are at significantly elevated risk of postsurgery complications and merit closer monitoring by health care professionals after bariatric surgery. It is now recognized that genetic factors influence individual patient's response to drug used in anesthesia and analgesia. Among the many drug administered by anesthetists, we focused in this pilot study on morphine, since morphine patient-controlled anesthesia in obese patients undergoing gastric bypass surgery is frequently prescribed. We examined the allelic frequency of three polymorphisms involved in morphine pharmacodynamics and pharmacokinetics in patients with body mass index (BMI) >40. One hundred and nine morbidly obese patients (BMI = 49.1 ± 7.7 kg/m²) were genotyped for three polymorphisms c.A118G of mu opioid receptor (OPRM1), c.C3435T of the P-glycoprotein gene (ABCB1), and p.Val158Met of catechol-O-methyltransferase gene (COMT). Allelic frequencies were 118G-0.22, C3435-0.55, and 158Met-0.5 in our whole population and 0.23, 0.5, and 0.47 in Caucasian population. Allelic frequencies did not differ according to gender. Mean BMI did no differ according to the allelic variant. OPRM1118G allele was more frequent in our population than in most previously described European populations. Since the concept of "personalized medicine" promises to individualize therapeutics and optimize medical treatment in term of efficacy and safety, especially when prescribing drugs with a narrow therapeutic index such as morphine, further clinical studies examining the clinical consequences of the OPRM1 c.A118G polymorphism in patients undergoing gastric bypass surgery are needed.

The role of the Asn40Asp polymorphism of the mu opioid receptor gene (OPRM1) on alcoholism etiology and treatment: a critical review

The endogenous opioid system has been implicated in the pathophysiology of alcoholism as it modulates the neurobehavioral effects of alcohol. A variant in the mu opioid receptor gene (OPRM1), the Asn40Asp polymorphism, has received attention as a functional variant that may influence a host of behavioral phenotypes for alcoholism as well as clinical response to opioid antagonists. This paper will review converging lines of evidence on the effect of the Asn40Asp SNP on alcoholism phenotypes, including: (i) genetic association studies; (ii) behavioral studies of alcoholism; (iii) neuroimaging studies; (iv) pharmacogenetic studies and clinical trials; and (v) preclinical animal studies. Together, these lines of research seek to elucidate the effects of this functional polymorphism on alcoholism etiology and treatment response.

Implicit processes in pathological skin picking: responses to skin irregularities predict symptom severity and treatment susceptibility

BACKGROUND AND OBJECTIVES

Implicit cognitive processes are relevant in understanding the development and maintenance of psychopathology and dysfunctional behaviours. The present study investigated the role of implicit processes in pathological skin picking (PSP).

METHODS

Using an Approach-Avoidance Task (AAT), we examined automatic response tendencies towards skin picking-related photographs in a sample of 34 college students who suffered from PSP and participated in a randomized, waiting-list controlled treatment study.

RESULTS

In comparison to a control sample (n = 49), PSP patients displayed significantly decelerated reaction times (distraction) in response to photographs of skin irregularities and a tendency to respond with avoidance to photographs of skin irregularities. Both distraction and avoidance in reaction to photographs of skin irregularities were significantly associated with current skin picking severity. Moreover, the strength of distraction in response to skin irregularities predicted unique variance in skin picking severity at post-measurement, over and above the effect of skin picking severity at pre-measurement and the effect of treatment condition. For the treatment condition, higher initial distraction predicted better treatment outcome (lower skin picking severity at post-measurement), whereas it predicted symptom deterioration at post-treatment for untreated participants.

LIMITATIONS

The specific characteristics of PSP patients (mainly female university students) and the relatively small sample size may compromise generalizability of findings.

CONCLUSIONS

In PSP, affective distraction in response to skin irregularities seems to characterize an important process related to symptom severity as well as treatment susceptibility.

The moderating role of working memory capacity and alcohol-specific rule-setting on the relation between approach tendencies and alcohol use in young adolescents

BACKGROUND

Dual process models of alcohol addiction propose that the transition from normative alcohol consumption to heavy drinking is the result of an imbalance in interplay between relatively impulsive or automatic and reflective or controlled processes. The current study examines whether impulsive and reflective processes are also detectable in a sample of adolescents with limited alcohol use.

METHODS

Specifically, we tested the interaction between alcohol approach tendencies and 2 types of reflective processes, working memory capacity (WMC) and alcohol-specific rule-setting, on changes in alcohol use of 238 young adolescents (mean age: 13.82 years). Gender differences in these associations were also explored.

RESULTS

Results showed that WMC did not moderate the relation between approach tendencies and subsequent alcohol use, whereas rule-setting did, with stronger associations between approach tendencies and alcohol use for male adolescents reporting more permissive parents than male adolescents with parents enforcing stricter rules involving alcohol use. Associations between approach tendencies and subsequent alcohol use did not emerge for female adolescents.

CONCLUSIONS

Results indicate that even in a sample of adolescents with limited drinking experience, automatic processes are positively associated with alcohol use for male adolescents that are not motivated by parents to control their drinking.

Components of behavioural impulsivity and automatic cue approach predict unique variance in hazardous drinking

RATIONALE

Hazardous drinking is associated with both increased impulsivity and automatic approach tendencies elicited by alcohol-related cues. However, impulsivity is a multi-factorial construct, and it is currently unclear if all components of impulsivity are associated with heavy drinking. Furthermore, emerging evidence suggests that the relationships between hazardous drinking and automatic alcohol cognitions may be moderated by individual differences in impulsivity.

OBJECTIVES

The aim of this study was to investigate the independence of measures of impulsivity and their association with hazardous drinking, and to examine if the relationship between hazardous drinking and automatic alcohol approach tendencies would be moderated by individual differences in impulsivity.

METHODS

Ninety-seven social drinkers (65 female) completed questionnaire measures of trait impulsivity, alcohol consumption and hazardous drinking. Participants also completed computerised measures of automatic alcohol approach tendencies (stimulus-response compatibility (SRC) task), and two behavioural measures of impulsivity (Go/No-go and delay discounting tasks).

RESULTS

Principal component analysis revealed that the two measures of behavioural impulsivity were distinct from each other and from self-reported trait impulsivity, although self-reported non-planning impulsivity loaded on to two factors (trait impulsivity and delay discounting). Furthermore, all measures of impulsivity predicted unique variance in hazardous drinking as did automatic alcohol approach tendencies, although the latter relationship was not moderated by impulsivity.

CONCLUSIONS

These results indicate that multiple components of impulsivity and automatic alcohol approach tendencies explain unique variance in hazardous drinking.

COMT and ALDH2 polymorphisms moderate associations of implicit drinking motives with alcohol use

Dual process models of addiction emphasize the importance of implicit (automatic) cognitive processes in the development and maintenance of substance use behavior. Although genetic influences are presumed to be relevant for dual process models, few studies have evaluated this possibility. The current study examined two polymorphisms with functional significance for alcohol use behavior (COMT Val158Met and ALDH2*2) in relation to automatic alcohol cognitions and tested additive and interactive effects of genotype and implicit cognitions on drinking behavior. Participants were college students (n = 69) who completed Implicit Association Tasks (IATs) designed to assess two classes of automatic drinking motives (enhancement motives and coping motives). Genetic factors did not show direct associations with IAT measures; however, COMT and ALDH2 moderated associations of implicit coping motives with drinking outcomes. Interaction effects indicated that associations of implicit motives with drinking outcomes were strongest in the context of genetic variants associated with relatively higher risk for alcohol use (COMT Met and ALDH2*1). Associations of genotype with drinking behavior were observed for ALDH2 but not COMT. These findings are consistent with the possibility that genetic risk or protective factors could potentiate or mitigate the influence of reflexive cognitive processes on drinking behavior, providing support for the evaluation of genetic influences in the context of dual process models of addiction.

Alcohol-related effects on automaticity due to experimentally manipulated conditioning

BACKGROUND

The use of alcohol is associated with various forms of automatic processing, such as approach tendencies and attentional biases, which may play a role in addictive behavior. The development of such automaticity has generally occurred well before subjects perform tasks designed to detect them. Although it seems plausible that this development involves some form of alcohol-related conditioning, this process is not usually included in the experimental procedure.

METHODS

The development of automaticity involving alcoholic or nonalcoholic stimuli was experimentally manipulated via a conditioning task. Subjects were presented with pairs of stimuli from a set of 4 stimuli: 2 pictures of alcoholic beverages, and 2 pictures of nonalcoholic beverages. One of the alcoholic and 1 of the nonalcoholic beverages was associated with reward, the other stimuli with punishment. Subjects had to learn to select the rewarded stimuli from pairs of 1 rewarded and 1 punished stimulus. The task, thus experimentally established reward versus punishment stimulus-response-outcome associations, for alcoholic and for nonalcoholic stimuli. Subsequently, a cued reversal task was used to test automaticity involving alcoholic versus nonalcoholic, and rewarded versus punished stimuli.

RESULTS

An association was found between heavier drinking and an alcohol-related conditioning bias: heavier drinkers had more difficulty overcoming a conditioned response when it involved selecting a previously punished nonalcoholic stimulus over a previously rewarded alcoholic stimulus.

CONCLUSIONS

The study provided novel information on secondary reinforcement involving alcoholic stimuli: heavier drinkers may more easily develop automaticity related to alcohol-reward contingencies. This may have implications for interventions and the interpretation of findings concerning alcohol-related automatic processing.

Prefrontal activation patterns of automatic and regulated approach-avoidance reactions - a functional near-infrared spectroscopy (fNIRS) study

INTRODUCTION

The present pilot study investigated cortical processes during automatic and regulated approach-avoidance reactions for the first time. METHODS 1: In 15 healthy volunteers, prefrontal activity was measured with functional near-infrared spectroscopy (fNIRS) during performance of a joystick version of the Approach-Avoidance Task (AAT). In experiment 1, participants approached (pulled towards their body) and avoided (pushed away from their body) positive and negative pictures. RESULTS 1: Incompatible, regulated reactions (avoid positive, approach negative) compared to compatible, automatic reactions (approach positive, avoid negative) caused stronger activation in terms of a decrease of deoxygenated haemoglobin (HHb) in right dorsolateral prefrontal cortex (DLPFC) (i.e., in one of the main instances for behavioural control in humans). METHODS 2: In the context of pathologically enhanced approach tendencies in addiction disorders and of planned future studies, we presented alcohol and non-alcohol pictures in experiment 2. RESULTS 2: Here, left anterior lateral orbitofrontal cortex as part of the general reward system processing secondary rewards showed stronger activation in terms of increased oxygenated haemoglobin (O(2)Hb) during approaching compared to avoiding alcohol pictures. This difference was positively correlated with participants' expectation about beneficial effects of alcohol in terms of emotional regulation.

DISCUSSION

Despite some limitations due to the pilot character of the study, our results suggest that further combinations of the AAT and functional imaging methods will reveal detailed insight into neuronal mechanisms constituting approach-avoidance as basic behavioural principles and into specifically altered sub-processes in alcohol dependence.

The effect of the OPRM1 and DRD4 polymorphisms on the relation between attentional bias and alcohol use in adolescence and young adulthood

BACKGROUND

The incentive sensitization theory posits that in the transition from sporadic to problematic alcohol use, the incentive value of alcohol increases (wanting) while its hedonic effects (liking) do not change or decreases. The effect of the OPRM1 c.118A>G polymorphism, associated with liking and wanting, and the DRD4-VNTR polymorphism, related to wanting, on the relation between attentional bias and alcohol use was investigated.

METHODS

A total of 195 young adolescents (Study 1) and 86 young adult male heavy drinkers (Study 2) completed a visual probe test. Saliva samples were collected to test both polymorphisms.

RESULTS

In Study 1, attentional bias was positively associated with adolescent alcohol use only for OPRM1 G-allele carriers. In Study 2, attentional bias was positively associated with problem drinking for carriers of a DRD4 long allele.

DISCUSSION

It is tentatively proposed that an attentional bias for alcohol is related most strongly to liking and wanting in early adolescents, while in young adults, an attentional bias may reflect wanting. In addition, individual differences associated with two both genetic markers should be taken into account when examining the relation between attentional bias and alcohol use.

To approach or avoid alcohol? Automatic and self-reported motivational tendencies in alcohol dependence

BACKGROUND

Motivational conflict is central to alcohol dependence, with patients reporting motivation to limit their drinking at the same time as urges to drink alcohol. In addition, dual process models of addiction emphasise the power of automatic cognitive processes, particularly automatic approach responses elicited by alcohol-related cues, as determinants of drinking behavior. We aimed to examine the strength of automatic and self-reported alcohol approach and avoidance tendencies among alcohol-dependent inpatients relative to matched controls.

METHODS

A total of 63 alcohol-dependent patients undergoing detoxification and 64 light-drinking controls completed a stimulus-response compatibility (SRC) task, which assesses the speed of categorization of alcohol-related pictures by making symbolic approach and avoidance movements. We also included modified versions of the SRC task to assess automatic motivational conflict, that is, strong approach and avoidance tendencies elicited simultaneously by alcohol-related cues.

RESULTS

There were no differences between alcohol-dependent patients and controls on the SRC task, although individual differences in the quantity of alcohol consumed before entering treatment were significantly positively correlated with the strength of approach (but not avoidance) tendencies elicited by alcohol-related cues. Automatic approach tendencies were also positively correlated with self-reported "approach" inclinations and negatively correlated with self-reported "avoidance" inclinations.

CONCLUSIONS

Although alcohol-dependent patients and matched controls did not differ on automatic approach and avoidance tendencies elicited by alcohol-related cues, individual differences in the quantity of alcohol consumed before entering treatment were associated with the strength of automatic approach tendencies elicited by alcohol cues.

Reaching out towards cannabis: approach-bias in heavy cannabis users predicts changes in cannabis use

AIMS

Repeated drug exposure can lead to an approach-bias, i.e. the relatively automatically triggered tendencies to approach rather that avoid drug-related stimuli. Our main aim was to study this approach-bias in heavy cannabis users with the newly developed cannabis Approach Avoidance Task (cannabis-AAT) and to investigate the predictive relationship between an approach-bias for cannabis-related materials and levels of cannabis use, craving, and the course of cannabis use.

DESIGN, SETTINGS AND PARTICIPANTS

Cross-sectional assessment and six-month follow-up in 32 heavy cannabis users and 39 non-using controls.

MEASUREMENTS

Approach and avoidance action-tendencies towards cannabis and neutral images were assessed with the cannabis AAT. During the AAT, participants pulled or pushed a joystick in response to image orientation. To generate additional sense of approach or avoidance, pulling the joystick increased picture size while pushing decreased it. Craving was measured pre- and post-test with the multi-factorial Marijuana Craving Questionnaire (MCQ). Cannabis use frequencies and levels of dependence were measured at baseline and after a six-month follow-up.

FINDINGS

Heavy cannabis users demonstrated an approach-bias for cannabis images, as compared to controls. The approach-bias predicted changes in cannabis use at six-month follow-up. The pre-test MCQ emotionality and expectancy factor were associated negatively with the approach-bias. No effects were found on levels of cannabis dependence.

CONCLUSIONS

Heavy cannabis users with a strong approach-bias for cannabis are more likely to increase their cannabis use. This approach-bias could be used as a predictor of the course of cannabis use to identify individuals at risk from increasing cannabis use.

Testing the validity of implicit measures of wanting and liking

BACKGROUND AND OBJECTIVES

Over the last decade, there has been a surge of studies examining implicit processes underlying addiction. Some implicit measures are assumed to reflect "liking" whereas other implicit measures are assumed to reflect "wanting". There is, however, little evidence to back up this claim. We examined whether implicit and explicit measures of wanting and of liking are differentially sensitive to manipulations of wanting and expected that these manipulations would affect primarily measures of wanting.

METHODS

Smokers and non-smokers performed both implicit and explicit measures that are assumed to assess wanting and liking for smoking. Smokers were tested once immediately after smoking, and once after 12 h of nicotine-deprivation.

RESULTS

IAT results suggested that smokers showed more implicit liking for nicotine when they were deprived than when they were satiated, whereas there were no differences in wanting. Smokers also seemed to show both more implicit wanting and more implicit liking for nicotine compared to non-smokers. Explicit measures did yield the expected results in that smokers reported to want nicotine more when they were deprived, whereas there were smaller differences in liking.

CONCLUSIONS

We found little support for the assumption that implicit measures of wanting and liking capture different processes. Researchers should thus be cautious in drawing conclusions about wanting and liking on the basis of these measures.

Pharmacogenomics of the human µ-opioid receptor

The µ-opioid receptor is a primary target for clinically important opioid analgesics, including morphine, fentanyl and methadone. Many genetic variations have been identified in the human µ-opioid receptor MOP gene (OPRM1), and their implications have been reported in the effects of opioid drugs and susceptibility to drug dependence. Interestingly, agonistic and antagonistic opioid effects are inversely associated with the A118G polymorphism genotype. The A118G polymorphism may also be associated with substance dependence and susceptibility to other disorders, including epilepsy and schizophrenia. The IVS1+A21573G, IVS1-T17286C, and TAA+A5359G polymorphisms in the OPRM1 gene may be associated with alcohol, opioid and tobacco dependence, respectively. However, some studies have failed to confirm the correlations between the polymorphisms and opioid effects and substance dependence. Further studies are needed to elucidate the molecular mechanisms underlying the effects of OPRM1 polymorphisms.

Relapse prevention for addictive behaviors

The Relapse Prevention (RP) model has been a mainstay of addictions theory and treatment since its introduction three decades ago. This paper provides an overview and update of RP for addictive behaviors with a focus on developments over the last decade (2000-2010). Major treatment outcome studies and meta-analyses are summarized, as are selected empirical findings relevant to the tenets of the RP model. Notable advances in RP in the last decade include the introduction of a reformulated cognitive-behavioral model of relapse, the application of advanced statistical methods to model relapse in large randomized trials, and the development of mindfulness-based relapse prevention. We also review the emergent literature on genetic correlates of relapse following pharmacological and behavioral treatments. The continued influence of RP is evidenced by its integration in most cognitive-behavioral substance use interventions. However, the tendency to subsume RP within other treatment modalities has posed a barrier to systematic evaluation of the RP model. Overall, RP remains an influential cognitive-behavioral framework that can inform both theoretical and clinical approaches to understanding and facilitating behavior change.

Addiction, adolescence, and the integration of control and motivation

The likelihood of initiating addictive behaviors is higher during adolescence than during any other developmental period. The differential developmental trajectories of brain regions involved in motivation and control processes may lead to adolescents' increased risk taking in general, which may be exacerbated by the neural consequences of drug use. Neuroimaging studies suggest that increased risk-taking behavior in adolescence is related to an imbalance between prefrontal cortical regions, associated with executive functions, and subcortical brain regions related to affect and motivation. Dual-process models of addictive behaviors are similarly concerned with difficulties in controlling abnormally strong motivational processes. We acknowledge concerns raised about dual-process models, but argue that they can be addressed by carefully considering levels of description: motivational processes and top-down biasing can be understood as intertwined, co-developing components of more versus less reflective states of processing. We illustrate this with a model that further emphasizes temporal dynamics. Finally, behavioral interventions for addiction are discussed. Insights in the development of control and motivation may help to better understand - and more efficiently intervene in - vulnerabilities involving control and motivation.

Individual variation in the motivational properties of cocaine

Cues in the environment associated with drug use draw the attention of addicts, elicit approach, and motivate drug-seeking and drug-taking behavior, making abstinence difficult. However, preclinical studies have identified large individual differences in the extent to which reward cues acquire these incentive motivational properties. For example, only in some rats does a spatially discrete food cue become attractive, eliciting approach and engagement with it, and acts as an effective conditioned reinforcer. Moreover, a discrete cocaine cue also acquires greater motivational control over behavior in rats prone to attribute incentive salience to a food cue. In this study, we asked whether there is similar individual variation in the extent to which interoceptive cues produced by cocaine itself instigate cocaine-seeking behavior. After quantifying individual variation in the propensity to attribute incentive salience to a food cue, rats were trained to self-administer cocaine in the absence of an explicit conditional stimulus. We then assessed motivation for cocaine by: (1) performance on a progressive ratio schedule, and (2) the degree to which a cocaine 'prime' reinstated cocaine-seeking following extinction of self-administration behavior. We found that rats prone to attribute incentive salience to a food cue worked harder for cocaine, and showed more robust cocaine-induced reinstatement. We conclude that there is considerable individual variation in the motivational properties of cocaine itself, and this can be predicted by the propensity to attribute incentive salience to reward cues.

Resisting temptation: decreasing alcohol-related affect and drinking behavior by training response inhibition

According to dual-process models, excessive alcohol use emerges when response inhibition ability is insufficient to inhibit automatic impulses to drink alcohol. This study examined whether strengthening response inhibition for alcohol-related cues decreases alcohol intake. Fifty-two heavy drinking students were randomly assigned to one of two conditions: In the beer/no-go condition, participants performed a go/no-go task that consistently paired alcohol-related stimuli with a stopping response, to increase response inhibition for alcohol-related stimuli. In the beer/go condition, in contrast, participants were always required to respond to alcohol-related stimuli during the go/no-go task. Before and after the go/no-go manipulation, we measured weekly alcohol intake and implicit attitudes toward alcohol. In addition, we measured alcohol consumption during a taste test immediately after the go/no-go manipulation. Following the manipulation, participants in the beer/no-go condition demonstrated significantly increased negative implicit attitudes toward alcohol, and a significant reduction in weekly alcohol intake, while participants in the beer/go condition showed a non-significant increase in implicit positive attitudes toward alcohol and a significant increase in weekly alcohol intake. This study demonstrates that repeatedly stopping prepotent responses toward alcohol-related stimuli can be an effective strategy to reduce excessive alcohol use.

Approach and Avoidance Tendencies in Spider Fearful Children: The Approach-Avoidance Task

Fear in children is associated with the tendency to avoid situations related to the fear. In this study, the Approach-Avoidance Task (AAT) was evaluated as a test of automatic behavioral avoidance tendencies in children. A sample of 195 children aged between 9 and 12 years completed an AAT, a Behavioral Assessment Task (BAT), and two spider fear questionnaires. The results indicate that all children showed an automatic avoidance tendency in response to spider pictures, but not pictures of butterflies or neutral pictures. Girls who reported more fear of spiders on the self-reports and behaved more anxiously during the BAT also showed a greater avoidance tendency in the AAT. These relationships were absent in boys.

Retraining Automatic Action Tendencies Changes Alcoholic Patients’ Approach Bias for Alcohol and Improves Treatment Outcome

This study tested the effects of a new cognitive-bias modification (CBM) intervention that targeted an approach bias for alcohol in 214 alcoholic inpatients. Patients were assigned to one of two experimental conditions, in which they were explicitly or implicitly trained to make avoidance movements (pushing a joystick) in response to alcohol pictures, or to one of two control conditions, in which they received no training or sham training. Four brief sessions of experimental CBM preceded regular inpatient treatment. In the experimental conditions only, patients’ approach bias changed into an avoidance bias for alcohol. This effect generalized to untrained pictures in the task used in the CBM and to an Implicit Association Test, in which alcohol and soft-drink words were categorized with approach and avoidance words. Patients in the experimental conditions showed better treatment outcomes a year later. These findings indicate that a short intervention can change alcoholics’ automatic approach bias for alcohol and may improve treatment outcome.

Appetitive and regulatory processes in young adolescent drinkers

Dual-process models of addiction propose that alcohol (mis)use develops because of an imbalance between a fast automatic appetitive system, in which stimuli are valued in terms of their emotional and motivational significance and a slower controlled regulatory system, which acts on deliberate considerations. This study focused on the automatic and regulatory processes that are involved in the early stages of young adolescent alcohol use. Participants were 43 young adolescent drinkers, who completed an explicit alcohol valence measure, two versions of an Affective Simon Task (AST), a working memory task and an alcohol use questionnaire. Alcohol use was associated with relatively positive self-reported valence of alcohol pictures, especially for adolescents with lower inhibition capacity. The Affective Simon Tasks did not show stronger automatic approach tendencies in heavier drinkers. This study suggests that in early stages of alcohol use appetitive valence is a more important stimulator for the initiation of alcohol use than automatic approach tendencies, and supports the view that young adolescents with low inhibition capacity are especially at risk for developing alcohol misuse. Prevention therefore should be focused on reducing the attractive valence of alcoholic drinks and strengthening the cognitive control of at-risk children.

Endogenous opiates and behavior: 2009

This paper is the 32nd consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2009 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).

Evaluating a cognitive model of ALDH2 and drinking behavior

BACKGROUND

Despite evidence for genetic influences on alcohol use and alcohol-related cognitions, genetic factors and endophenotypes are rarely incorporated in cognitive models of drinking behavior. This study evaluated a model of ALDH2 and drinking behavior stipulating cognitive factors and alcohol sensitivity as accounting for genetic influences on drinking outcomes.

METHODS

Participants were Asian-American young adults (n = 171) who completed measures of alcohol cognitions (drinking motives, drinking refusal self-efficacy, and alcohol expectancies), alcohol sensitivity, drinking behavior, and alcohol-related problems as part of a prospective study. Structural equation modeling (SEM) evaluated a model of drinking behavior that stipulated indirect effects of ALDH2 on drinking outcomes through cognitive variables and alcohol sensitivity.

RESULTS

The full model provided an adequate fit to the observed data, with the measurement model explaining 63% of the variance in baseline heavy drinking and 50% of the variance in alcohol-related problems at follow-up. Associations of ALDH2 with cognitive factors and alcohol sensitivity were significant, whereas the association of ALDH2 with drinking was not significant with these factors included in the model. Mediation tests indicated significant indirect effects of ALDH2 through drinking motives, drinking refusal self-efficacy, and alcohol sensitivity.

CONCLUSIONS

Results are consistent with the perspective that genetic influences on drinking behavior can be partly explained by learning mechanisms and implicate cognitive factors as important for characterizing associations of ALDH2 with drinking.

Stress-induced and cue-induced craving for alcohol in heavy drinkers: Preliminary evidence of genetic moderation by the OPRM1 and CRH-BP genes

BACKGROUND

Neurobiological theories of addiction have highlighted disruption in stress pathways as a central feature of addictive disorders, and pharmacological treatments targeting stress mechanisms hold great promise. This study examines genetic determinants of stress-induced and cue-induced craving in heavy drinkers by testing single-nucleotide polymorphisms (SNPs) of the corticotrophin-releasing hormone binding protein (CRH-BP) gene and the mu-opioid receptor (OPRM1) gene.

METHODS

This study combines guided imagery stress exposure and in vivo alcohol cue exposure in a sample of 64 (23 women) non-treatment-seeking heavy drinkers.

RESULTS

Analyses, uncorrected for multiple comparisons, revealed that a tag SNP of the CRH-BP gene (rs10055255) moderated stress-induced craving in this sample. The same SNP predicted greater affective responses to the stress manipulation, including greater levels of subjective tension and negative mood. The Asp40 allele of the OPRM1 was associated with greater cue-induced alcohol craving following the neutral imagery condition.

CONCLUSIONS

These initial results extend recent preclinical and clinical findings implicating the CRH-BP in stress-related alcoholism and confirm the role of the Asp40 allele of the OPRM1 gene in reward-driven alcohol phenotypes. Human laboratory models of stress and cue-induced craving may be useful in pharmacotherapy development targeting dysregulation of stress systems. Larger studies are needed to validate these preliminary findings, which should also be extended to clinical samples.

Automatic avoidance tendencies in individuals with contamination-related obsessive-compulsive symptoms

We used an approach-avoidance task (AAT) to examine response to threatening stimuli in 20 individuals high in contamination-related obsessive-compulsive symptoms (HCs) and 21 individuals low in contamination-related obsessive-compulsive symptoms (LCs). Participants were instructed to respond to contamination-related and neutral pictures by pulling a joystick towards themselves or by pushing it away from themselves. Moving the joystick changed the size of the image to simulate approaching or distancing oneself from the object. Consistent with our hypothesis, the HC group was significantly slower in pulling contamination-related pictures than in pulling neutral pictures, whereas in the LC group there was no difference between speed of pulling contamination-related pictures and neutral pictures. Contrary to our hypothesis, we did not find support for faster pushing away of contamination-related pictures than neutral pictures by the HC group. Moreover, the degree of avoidance of contamination-related stimuli when pulling - but not when pushing - was significantly correlated with self-reported contamination-related obsessive-compulsive symptoms. These results suggest a biased behavioral response for threatening objects in individuals high in contamination fears only when inhibiting the prepotent response to avoid threatening stimuli and not when performing a practiced avoidance response. Thus, our results validate the use of the AAT as a measure of inhibited and uninhibited automatic avoidance reactions to emotional information in individuals with contamination-related obsessive-compulsive symptoms.

Acute alcohol effects on inhibitory control and implicit cognition: implications for loss of control over drinking

Alcohol impairs inhibitory control, and it alters implicit alcohol cognitions including attentional bias and implicit associations. These effects are seen after doses of alcohol which do not lead to global impairments in cognitive performance. We review studies which demonstrate that the effects of alcohol on inhibitory control are associated with the ability of alcohol to prime alcohol-seeking behavior. We also hypothesize that alcohol-induced changes in implicit alcohol cognitions may partially mediate alcohol-induced priming of the motivation to drink. Based on contemporary theoretical models and conceptualizations of executive function, impulsivity, and the motivational salience of alcohol-related cues, we speculate on other aspects of cognition that may underlie alcohol's effects on alcohol seeking. Inconsistencies in existing research and priorities for future research are highlighted, including dose effects and the potential interactions between chronic heavy drinking and the acute effects of alcohol on these cognitive processes.

OPRM1 SNP (A118G): involvement in disease development, treatment response, and animal models

Endogenous opioids acting at mu-opioid receptors mediate many biological functions. Pharmacological intervention at these receptors has greatly aided in the treatment of acute and chronic pain, in addition to other uses. However, the development of tolerance and dependence has made it difficult to adequately prescribe these therapeutics. A common single nucleotide polymorphism (SNP), A118G, in the mu-opioid receptor gene can affect opioid function and, consequently, has been suggested to contribute to individual variability in pain management and drug addiction. Investigation into the role of A118G in human disease and treatment response has generated a large number of association studies across various disease states as well as physiological responses. However, characterizing the functional consequences of this SNP and establishing if it causes or contributes to disease phenotypes have been significant challenges. In this manuscript, we will review a number of association studies as well as investigations of the functional impact of this gene variant. In addition, we will describe a novel mouse model that was generated to recapitulate this SNP in mice. Evaluation of models that incorporate known human genetic variants into a tractable system, like the mouse, will facilitate the understanding of discrete contributions of SNPs to human disease.

Consilient research approaches in studying gene x environment interactions in alcohol research

This review article discusses the importance of identifying gene-environment interactions for understanding the etiology and course of alcohol use disorders and related conditions. A number of critical challenges are discussed, including the fact that there is no organizing typology for classifying different types of environmental exposures, many key human environmental risk factors for alcohol dependence have no clear equivalents in other species, much of the genetic variance of alcohol dependence in human is not 'alcohol specific', and the potential range of gene-environment interactions that could be considered is so vast that maintaining statistical control of Type 1 errors is a daunting task. Despite these and other challenges, there appears to be a number of promising approaches that could be taken in order to achieve consilience and ecologically valid translation between human alcohol dependence and animal models. Foremost among these is to distinguish environmental exposures that are thought to have enduring effects on alcohol use motivation (and self-regulation) from situational environmental exposures that facilitate the expression of such motivations but do not, by themselves, have enduring effects. In order to enhance consilience, various domains of human approach motivation should be considered so that relevant environmental exposures can be sampled, as well as the appropriate species to study them in (i.e. where such motivations are ecologically relevant). Foremost among these are social environments, which are central to the initiation and escalation of human alcohol consumption. The value of twin studies, human laboratory studies and pharmacogenetic studies is also highlighted.

Retraining automatic action-tendencies to approach alcohol in hazardous drinkers

AIMS

The main aim of this study was to test whether automatic action-tendencies to approach alcohol can be modified, and whether this affects drinking behaviour.

DESIGN AND PARTICIPANTS

Forty-two hazardous drinkers were assigned randomly to a condition in which they were implicitly trained to avoid or to approach alcohol, using a training variety of the alcohol Approach Avoidance Test (AAT). Participants pushed or pulled a joystick in response to picture-format (landscape or portrait). The pictures depicted alcoholic or non-alcoholic drinks. Participants in the avoid-alcohol condition pushed most alcoholic and pulled most non-alcoholic drinks. For participants in the approach-alcohol condition these contingencies were reversed. After the implicit training, participants performed a taste test, including beers and soft drinks. Automatic action tendencies at post-test were assessed with the AAT, including both trained and untrained pictures, and with a different test (Implicit Association Test, IAT). We further tested effects on subjective craving.

RESULTS

Action tendencies for alcohol changed in accordance with training condition, with the largest effects in the clinically relevant avoid-alcohol condition. These effects occurred outside subjective awareness and generalized to new pictures in the AAT and to an entirely different test using words, rather than pictures (IAT). In relatively heavy drinking participants who demonstrated changed action tendencies in accordance with their training condition, effects were found on drinking behaviour, with participants in the approach-alcohol condition drinking more alcohol than participants in the avoid-alcohol condition. No effect was found on subjective craving.

CONCLUSIONS

Retraining automatic processes may help to regain control over addictive impulses, which points to new treatment possibilities.

Implicit cognition and addiction: a tool for explaining paradoxical behavior

Research on implicit cognition and addiction has expanded greatly during the past decade. This research area provides new ways to understand why people engage in behaviors that they know are harmful or counterproductive in the long run. Implicit cognition takes a different view from traditional cognitive approaches to addiction by assuming that behavior is often not a result of a reflective decision that takes into account the pros and cons known by the individual. Instead of a cognitive algebra integrating many cognitions relevant to choice, implicit cognition assumes that the influential cognitions are the ones that are spontaneously activated during critical decision points. This selective review highlights many of the consistent findings supporting predictive effects of implicit cognition on substance use and abuse in adolescents and adults; reveals a recent integration with dual-process models; outlines the rapid evolution of different measurement tools; and introduces new routes for intervention.