The habitual brain: an "adapted habit" theory of substance use disorders

Distress Tolerance is Indirectly Related to Nicotine Use through the Smoking Motives

BACKGROUND AND OBJECTIVES

Previous research has shown that low ability to tolerate distress is indirectly related to problematic substance use through the substance use motives. This topic has been previously researched in alcohol and cannabis use; however, it has not yet been explored in tobacco use. We studied whether distress tolerance is indirectly associated with nicotine dependence through motives of tension reduction and habitual smoking.

DESIGN AND METHODS

A total sample of 451 (230 of which were women) daily and occasional Polish smokers (aged from 18 to 60 years) reported distress tolerance, motives for smoking, and nicotine dependence. We then conducted a mediation analysis with bootstrapping using PROCESS macro.

RESULTS

Distress tolerance was indirectly related to nicotine dependence through both motives independently. In terms of the sequential model, there was a significant indirect effect of distress tolerance on nicotine dependence through smoking motives: tension reduction and habit. The total effect of distress tolerance on nicotine dependence was insignificant.

CONCLUSIONS

Our findings suggest that individuals with low distress tolerance are especially prone to nicotine dependence if they use smoking as a coping mechanism and it becomes habitual. The current study highlights the importance of a multidimensional approach in dealing with nicotine dependence.

Linking RDoC and HiTOP: A new interface for advancing psychiatric nosology and neuroscience

The Research Domain Criteria (RDoC) and the Hierarchical Taxonomy of Psychopathology (HiTOP) represent major dimensional frameworks proposing two alternative approaches to accelerate progress in the way psychopathology is studied, classified, and treated. RDoC is a research framework rooted in neuroscience aiming to further the understanding of transdiagnostic biobehavioral systems underlying psychopathology and ultimately inform future classifications. HiTOP is a dimensional classification system, derived from the observed covariation among symptoms of psychopathology and maladaptive traits, which seeks to provide more informative research and treatment targets (i.e., dimensional constructs and clinical assessments) than traditional diagnostic categories. This article argues that the complementary strengths of RDoC and HiTOP can be leveraged in order to achieve their respective goals. RDoC's biobehavioral framework may help elucidate the underpinnings of the clinical dimensions included in HiTOP, whereas HiTOP may provide psychometrically robust clinical targets for RDoC-informed research. We present a comprehensive mapping between dimensions included in RDoC (constructs and subconstructs) and HiTOP (spectra and subfactors) based on narrative review of the empirical literature. The resulting RDoC-HiTOP interface sheds light on the biobehavioral correlates of clinical dimensions and provides a broad set of dimensional clinical targets for etiological and neuroscientific research. We conclude with future directions and practical recommendations for using this interface to advance clinical neuroscience and psychiatric nosology. Ultimately, we envision that this RDoC-HiTOP interface has the potential to inform the development of a unified, dimensional, and biobehaviorally-grounded psychiatric nosology.

Compulsivity in Alcohol Use Disorder and Obsessive Compulsive Disorder: Implications for Neuromodulation

Alcohol use Disorder (AUD) is one of the leading causes of morbidity and mortality worldwide. The progression of the disorder is associated with the development of compulsive alcohol use, which in turn contributes to the high relapse rate and poor longer term functioning reported in most patients, even with treatment. While the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) defines AUD by a cluster of symptoms, parsing its heterogeneous phenotype by domains of behavior such as compulsivity may be a critical step to improve outcomes of this condition. Still, neurobiological underpinnings of compulsivity need to be fully elucidated in AUD in order to better design targeted treatment strategies. In this manuscript, we review and discuss findings supporting common mechanisms between AUD and OCD, dissecting the construct of compulsivity and focusing specifically on characteristic disruptions in habit learning and cognitive control in the two disorders. Finally, neuromodulatory interventions are proposed as a probe to test compulsivity as key pathophysiologic feature of AUD, and as a potential therapy for the subgroup of individuals with compulsive alcohol use, i.e., the more resistant stage of the disorder. This transdiagnostic approach may help to destigmatize the disorder, and suggest potential treatment targets across different conditions.

The alcoholic brain: neural bases of impaired reward-based decision-making in alcohol use disorders

Neuroeconomics is providing insights into the neural bases of decision-making in normal and pathological conditions. In the neuropsychiatric domain, this discipline investigates how abnormal functioning of neural systems associated with reward processing and cognitive control promotes different disorders, and whether such evidence may inform treatments. This endeavor is crucial when studying different types of addiction, which share a core promoting mechanism in the imbalance between impulsive subcortical neural signals associated with immediate pleasurable outcomes and inhibitory signals mediated by a prefrontal reflective system. The resulting impairment in behavioral control represents a hallmark of alcohol use disorders (AUDs), a chronic relapsing disorder characterized by excessive alcohol consumption despite devastating consequences. This review aims to summarize available magnetic resonance imaging (MRI) evidence on reward-related decision-making alterations in AUDs, and to envision possible future research directions. We review functional MRI (fMRI) studies using tasks involving monetary rewards, as well as MRI studies relating decision-making parameters to neurostructural gray- or white-matter metrics. The available data suggest that excessive alcohol exposure affects neural signaling within brain networks underlying adaptive behavioral learning via the implementation of prediction errors. Namely, weaker ventromedial prefrontal cortex activity and altered connectivity between ventral striatum and dorsolateral prefrontal cortex likely underpin a shift from goal-directed to habitual actions which, in turn, might underpin compulsive alcohol consumption and relapsing episodes despite adverse consequences. Overall, these data highlight abnormal fronto-striatal connectivity as a candidate neurobiological marker of impaired choice in AUDs. Further studies are needed, however, to unveil its implications in the multiple facets of decision-making.

Systematic Review of Occupational Therapy in the Treatment of Addiction: Models, Practice, and Qualitative and Quantitative Research

OBJECTIVE

The authors conducted a systematic review of theoretical models, professional practice, and research findings to understand occupational therapy's role in the treatment of addiction.

METHOD

PubMed, Academic Search Premier, CINAHL, ERIC, OTseeker, and Google Scholar were searched to identify scientific journal articles, book chapters, or any other similar literature published from 1970 through July 2015 that addressed theoretical approaches, intervention models, and professional roles or were qualitative or quantitative studies in which occupational therapy had a central role.

RESULTS

The literature search yielded 16 theoretical and professional role studies, 8 qualitative studies, and 14 quantitative studies. All studies had low levels of evidence, and all were case series, sometimes with very small samples.

CONCLUSION

Although occupational therapy has been involved in the treatment of people with substance addiction and, more recently, with behavioral addictions for more than half a century, the research that has been published is poor.

The natural expression of individual differences in self-reported level of response to alcohol during ecologically assessed drinking episodes

RATIONALE

Low sensitivity to alcohol is a well-established risk factor for alcohol use disorder (AUD). However, little is known about how the low sensitivity phenotype is expressed on a fine-grained, momentary level in drinkers' daily experience.

OBJECTIVES

The objective of the study is to evaluate individual differences in subjective states and appraisals of alcoholic beverages during the ascending limb of real-world drinking episodes.

METHODS

Social drinkers (N = 398) with varying degrees of alcohol sensitivity as indexed by the Self-Rating of the Effects of Alcohol form (SRE; Schuckit et al. in Addiction 92:979-988, 1997a) recorded diary entries over a 3-week monitoring period (2576 drinking episodes containing 6546 moments). Hierarchical linear modeling was used to evaluate whether individual differences in alcohol sensitivity predicted differing intra-episode estimated blood alcohol concentration (eBAC) trajectories, ratings of subjective states, and drink appraisals.

RESULTS

Lower self-reported alcohol sensitivity was associated with consuming "too much, too fast," as indicated by a steeper slope of ascending eBAC. In models adjusted for momentary eBAC level, participants reporting lower alcohol sensitivity at baseline showed blunted subjective intoxication and drink-contingent punishment.

CONCLUSIONS

The results suggest that low sensitivity to alcohol is associated with a blunting of some forms of subjective feedback (i.e., perceptions of intoxication and punishment) that might typically encourage drinking restraint. This may 'tip the scales' toward excess consumption and could help to explain why a low alcohol sensitivity forecasts AUD.

Allen Cognitive Level Screen for the classification of subjects treated for addiction

Introduction The Cognitive Disabilities Model (CDM) is an occupational approach that can allow the classification of the functional-cognitive abilities of persons with addictions. The objective of the study was to explore the applicability of the ACLS-5 to assess a sample of persons undergoing addiction-rehabilitation treatment. Methods A sample of 232 participants was recruited from an outpatient treatment centre in Madrid (Spain). The ACLS-5, the Montreal Cognitive Assessment (MoCA), and the Prefrontal Symptom Inventory (PSI) were administered. Sociodemographic and addiction-related data were also obtained. Results Half of the sample showed serious deficits in functional cognition, which ultimately could be related to problems in their daily performance. Scores of ACLS-5 showed significant correlations with the severity of addiction, with those obtained with the MoCA, and with attentional symptoms on the PSI scale. Conclusions The data suggest the applicability of the ACLS-5 in assessing the degree of functional cognition in subjects treated for addiction, providing evidence to support ecological validity and facilitating the development of well-targeted cognitive rehabilitation programmes from an occupational perspective. The use of occupational-based instruments to assess the functioning of those with addictions is a requirement of occupational therapy professionals working in this general area.

Behavioral and neuroimaging evidence for overreliance on habit learning in alcohol-dependent patients

Substance dependence is characterized by compulsive drug-taking despite negative consequences. Animal research suggests an underlying imbalance between goal-directed and habitual action control with chronic drug use. However, this imbalance, and its associated neurophysiological mechanisms, has not yet been experimentally investigated in human drug abusers. The aim of the present study therefore was to assess the balance between goal-directed and habit-based learning and its neural correlates in abstinent alcohol-dependent (AD) patients. A total of 31 AD patients and 19 age, gender and education matched healthy controls (HC) underwent functional magnetic resonance imaging (fMRI) during completion of an instrumental learning task designed to study the balance between goal-directed and habit learning. Task performance and task-related blood oxygen level-dependent activations in the brain were compared between AD patients and healthy matched controls. Findings were additionally associated with duration and severity of alcohol dependence. The results of this study provide evidence for an overreliance on stimulus-response habit learning in AD compared with HC, which was accompanied by decreased engagement of brain areas implicated in goal-directed action (ventromedial prefrontal cortex and anterior putamen) and increased recruitment of brain areas implicated in habit learning (posterior putamen) in AD patients. In conclusion, this is the first human study to provide experimental evidence for a disturbed balance between goal-directed and habitual control by use of an instrumental learning task, and to directly implicate cortical dysfunction to overreliance on inflexible habits in AD patients.

Pre-adolescent alcohol expectancies: critical shifts and associated maturational processes

Children's alcohol expectancies shift in late childhood/early adolescence in ways thought to lead to increased risk for adolescent alcohol use. The precise nature of this shift and the maturational processes that may influence it remain to be clarified. To these ends, we compared expectancy endorsement by grade across four expectancy domains: positive, negative, arousal, and sedation, in a cross-sectional sample of 3rd-6th grade children attending afterschool programs (n = 299). Structural equation modeling (SEM) was then used to describe the relationships between expectancies and differences in (a) cognitive ability and concept formation, (b) risk-taking personality traits, and (c) social exposure or values regarding alcohol-related information. Results showed those children in higher grades endorsed significantly more positive, negative, and sedating expectancies for alcohol than their younger peers. Concept formation partially and fully mediated the relationships between grade and both positive and sedating expectancies, respectively, but not the relationship between grade and negative expectancies. Sensation seeking did not increase across grades in this sample, and the relationship between sensation seeking and positive expectancies was fully mediated by reported alcohol exposure and values. This study provides a basis for future exploration of developmental influences on alcohol expectancies, an understanding of which may be helpful in the design of prevention efforts targeting high-risk youth before adolescence.

WISDM primary and secondary dependence motives: associations with self-monitored motives for smoking in two college samples

The Wisconsin Inventory of Smoking Dependence Motives (WISDM) assesses 13 domains of smoking motivation emphasized by diverse theoretical perspectives. Emerging findings support a distinction between four primary dependence motives (PDM) indexing core features of tobacco dependence and nine secondary dependence motives (SDM) indexing accessory features. The current study explored the validity of this distinction using data from two samples (Ns=50 and 88) of college smokers who self-monitored their reasons for smoking with electronic diaries. PDM scores were associated with diary endorsement of habitual or automatic motives for smoking individual cigarettes, which are conceptually consistent with the content of the PDM subscales. SDM did not clearly predict conceptually related self-monitored motives when tested alone. However, when these two correlated scale composites were co-entered, PDM predicted being a daily vs. nondaily smoker, being higher in nicotine dependence, and smoking individual cigarettes because of habit or automaticity. Conversely, after PDM-SDM co-entry, the unique variance in the SDM composite predicted the tendency to report smoking individual cigarettes for situational or instrumental motives (e.g., to control negative affect). The results suggest that the PDM composite may reflect core motivational features of nicotine dependence in these young smokers. The relative prominence of primary motives in advanced or dependent use may be even clearer when motives for smoking are assessed in real time rather than reported via questionnaire.

Refining the tobacco dependence phenotype using the Wisconsin Inventory of Smoking Dependence Motives: II. Evidence from a laboratory self-administration assay

Prior analyses of the Wisconsin Inventory of Smoking Dependence Motives (Piper et al., 2004) implicated 4 subscales as primary dependence motives (PDM) indexing the core features of tobacco dependence, with the remaining subscales reflecting secondary dependence motives (SDM; Piper et al., 2008). The current study extended this work by examining the correlates of PDM, SDM, their subscales, and other indicators of dependence in an operant self-administration paradigm. Smokers (N = 58) worked for cigarette puffs under differing fixed ratio schedules. Analyses focused on predicting self-administration under conditions of minimal constraint on tobacco access and on withdrawal and craving under conditions of severe constraint. Results support a 2-factor model of dependence, with the PDM factor showing relatively stronger relations with tobacco self-administration and the SDM factor showing relatively stronger relations with withdrawal symptomatology and distress-related craving. The PDM appears to index core features of tobacco dependence, but susceptibility to deprivation-contingent distress and craving may be better indexed by SDM.

A self in the mirror: mirror neurons, self-referential processing, and substance use disorders

Mirror neurons in the Rhesus monkey and the mirror neuron system (MNS) in the human brain respond to actions that are executed by self and observed in another animal or person (i.e., imitated). The status of the MNS in humans is unclear, with some positive and some negative findings using electroencephalography and functional neuroimaging. We suggest that the fronto-parietal MNS may be disparate nodes or modules of a (poorly understood) self-referential processing system that is important in drug abuse and addiction. We then discuss some theories of the etiology of these disorders that emphasize the self. A modular approach to human brain organization and function (as opposed to strict localizationist or extreme globalist models) may resolve some issues surrounding the MNS and drug abuse.

Are "physiological" and "psychological" addiction really different? well, no! ... um, er, yes?

The distinction often made between psychological and physiological addiction is a form of mind-body dualism. Therefore, it is a false distinction. However, this does not imply that behavioral and autonomic symptoms of addiction have the same brain substrates. In fact, they likely do not, although there is some overlap.