Gambling disorder and other behavioral addictions: recognition and treatment

Shared gray matter alterations in individuals with diverse behavioral addictions: A voxel-wise meta-analysis

BACKGROUND AND AIMS

Numerous studies on behavioral addictions (BAs) have reported gray matter (GM) alterations in multiple brain regions by using voxel-based morphometry (VBM). However, findings are poorly replicated and it remains elusive whether distinct addictive behaviors are underpinned by shared abnormalities. In this meta-analysis, we integrated VBM studies on different BAs to investigate common GM abnormalities in individuals with BAs.

METHODS

Numerous studies on behavioral addictions (BAs) have reported gray matter (GM) alterations in multiple brain regions by using voxel-based morphometry (VBM). However, findings are poorly replicated and it remains elusive whether distinct addictive behaviors are underpinned by shared abnormalities. In this meta-analysis, we integrated VBM studies on different BAs to investigate common GM abnormalities in individuals with BAs.

RESULTS

Twenty studies including 505 individuals with BAs and 564 healthy controls met the inclusion criteria. Compared with healthy controls, individuals with BAs showed GM atrophy in the left anterior cingulate (extending to the left medial superior frontal gyrus and bilateral orbitofrontal gyrus), right putamen and right supplementary motor area. Subgroup analysis found heterogeneity in gender and subtypes of BAs. Meta-regression revealed that GM decreases in the left anterior cingulate and right supplementary motor area were positively correlated with addictive severity. Higher impulsivity was associated with smaller volume of the left anterior cingulate.

DISCUSSION AND CONCLUSIONS

Our findings on BAs were mainly derived from internet gaming disorder (IGD) and pathological gambling (PG) studies, preliminarily suggesting that GM atrophy in the prefrontal and striatal areas might be a common structural biomarker of BAs.

An addiction to seeking fortune-telling services: a case report

The paper describes a case report of a 36-years old female patient suffering from an addiction to seeking fortune-telling services, which is a type of behavioral addiction, or non-substance addiction. This condition is characterized by the addiction to various "occult services", fortune tellers and other representatives of nontraditional practices who are usually manipulative and self-serving. The authors reveal that this case report of fortune telling addiction possesses all of six components universal for addictions.In light of the increasing prevalence of various behavioral addictions, clinical psychiatrists should be aware of this phenomenon.

Dimensions of Impulsivity in Gambling Disorder

Impulsivity is a multidimensional construct. Although gambling disorder (GD) has been associated with high impulsivity, impulsivity across multiple domains has not been thoroughly investigated in this population. We first aimed to examine whether associations between three facets of impulsivity (response impulsivity, choice impulsivity and impulsive tendency) varied between GD patients and healthy controls (HC). We next aimed to evaluate relationships between these three types of impulsivity, as proposed by theoretical models of impulsivity, and their associations with GD severity. The sample included 97 treatment-seeking adult men with GD, diagnosed according to DSM-5 criteria, and 32 male HCs recruited from the general population. Greater impulsivity in all three domains was found in men with GD in comparison to men without GD. Associations between impulsivity facets were found in both groups, with response impulsivity being the only domain associated with GD severity. Our findings confirm that multiple domains of impulsivity are relevant in GD. Future studies should examine the extent to which treatments aimed at targeting specific aspects of impulsivity improve outcomes.

Gambling Phenotypes in Online Sports Betting

BACKGROUND AND OBJECTIVES

The Internet provides easy access to multiple types of gambling and has led to changes in betting habits. A severe rise in problematic gambling has been predicted among all sectors of the population, and studies are required to assess the emerging phenotypes related to the new structures of gambling activities. This study aimed to explore the existence of latent classes associated with gambling habits among treatment-seeking gamblers due to Online Sports Betting (OSB).

METHOD

Initial sample included n = 4,516 patients consecutively admitted for treatment in a hospital unit specialized in behavioral addictions. Two-step clustering analysis was used within the subsample of n = 323 patients who reported problems related with OSB, within a set of indicators including sociodemographics, psychopathological distress, personality, and severity of the gambling activity.

RESULTS

The prevalence of OSB as a main type of gambling problem in the study was 7.2% (95% confidence interval: 6.4 to 7.9%). Two latent clusters were identified, with differences in sociodemographics and clinical status. Cluster 1 (n = 247, 76.5%) grouped patients that were more affected due to the OSB behaviors, and it was characterized by non-married patients, lower socioeconomic position index, higher comorbidity with other substance related addictions, younger age, and early onset of the gambling activity, as well as higher debts due to the OSB, higher psychopathological distress, and a more dysfunctional personality profile. Cluster 2 (n = 76, 23.5%) grouped patients that were less affected by OSB, mostly married (or living with a stable partner), with higher social position levels, older age and older onset of the gambling activity, as well as a more functional psychopathological and personality profile.

CONCLUSION

The increasing understanding of latent classes underlying OSB phenotypes is essential in guiding the development of reliable screening tools to identify individuals highly vulnerable to addictive behaviors among Internet gamblers, as well as in planning prevention and treatment initiatives focused on the precise profiles of these patients.

Neuropharmacological and Neurogenetic Correlates of Opioid Use Disorder (OUD) As a Function of Ethnicity: Relevance to Precision Addiction Medicine

BACKGROUND

Over 100 people die daily from opioid overdose and $78.5B per year is spent on treatment efforts, however, the real societal cost is multifold greater. Alternative strategies to eradicate/manage drug misuse and addiction need consideration. The perception of opioid addiction as a social/criminal problem has evolved to evidence-based considerations of them as clinical disorders with a genetic basis. We present evaluations of the genetics of addiction with ancestryspecific risk profiles for consideration.

OBJECTIVE

Studies of gene variants associated with predisposition to substance use disorders (SUDs) are monolithic, and exclude many ethnic groups, especially Hispanics and African Americans. We evaluate gene polymorphisms that impact brain reward and predispose individuals to opioid addictions, with a focus on the disparity of research which includes individuals of African and Hispanic descent.

METHODOLOGY

PubMed and Google Scholar were searched for: Opioid Use Disorder (OUD), Genome- wide association studies (GWAS); genetic variants; polymorphisms, restriction fragment length polymorphisms (RFLP); genomics, epigenetics, race, ethnic group, ethnicity, ancestry, Caucasian/ White, African American/Black, Hispanic, Asian, addictive behaviors, reward deficiency syndrome (RDS), mutation, insertion/deletion, and promotor region.

RESULTS

Many studies exclude non-White individuals. Studies that include diverse populations report ethnicity-specific frequencies of risk genes, with certain polymorphisms specifically associated with Caucasian and not African-American or Hispanic susceptibility to OUD or SUDs, and vice versa.

CONCLUSION

To adapt precision medicine-based addiction management in a blended society, we propose that ethnicity/ancestry-informed genetic variations must be analyzed to provide real precision- guided therapeutics with the intent to attenuate this uncontrollable fatal epidemic.

Dopamine and Gambling Disorder: Prospects for Personalized Treatment

Purpose of Review

To address variation in the severity of gambling disorder, this review evaluates the contribution of mesocorticolimbic dopamine neurons to potential behavioral endophenotypes, the influence of individual differences in the dopamine system on gambling and related behaviors, and the possible role for dopaminergic medications in the treatment of gambling disorder.

Recent Findings

Newer work has suggested that dopaminergic dysfunction can lead to increased reward anticipation and a greater sensitivity to uncertainty, which in turn may drive addictive gambling behaviors. In addition, increased impulsivity, a well-recognized risk factor for gambling disorder, has been linked to dopaminergic dysfunction. More recently, emerging evidence has suggested that dopaminergic medications can influence the discounting of delayed rewards.

Summary

Dopaminergic drugs that increase the salience of long-term over short-term goals may ameliorate symptoms of impulsive individuals with gambling disorder. More broadly, improved understanding of intermediate behavioral and other phenotypes with a defined neurobiological substrate may allow for personalized treatment of gambling disorder and other psychiatric conditions.

Addictive behaviors in alcohol use disorder: dysregulation of reward processing systems and maladaptive coping strategies

DSM-5 has included within the substance-related and addictive disorders diagnostic category behavioral addictions, such as gambling disorder. Some scholars also considered ICD-11 compulsive sex as a behavioral addiction. Furthermore, an addiction model of dysfunctional eating behaviors has been proposed. Consistently, the existence of common addiction mechanisms related to substance and non-substance related disorders has been hypothesized. Nevertheless, this approach was called into question, especially considering alternative processes which might be implicated in such conditions. This study aims to compare these opposite theoretical positions concerning substance- and nonsubstance related disorders, investigating the latent structure of addictive behaviors among alcohol use disorder (AUD) individuals. Addictive behaviors were self-reported assessed using the Shorter PROMIS Questionnaire (SPQ). We recruited 456 (59.2% male; 40.8% female) AUD treatment-seeking patients. Two latent structures were tested using a confirmatory factor analytic approach. We compared a one-factor (i.e., common addiction mechanisms) with a two-factor solution (i.e., dysregulation of reward processing systems and maladaptive coping strategies). The two-factor solution showed adequate goodness-of-fit indexes. Specifically, dysregulation of the reward processing systems dimension predicted the SPQ illicit and prescription drugs, gambling, and sex subscales. Conversely, the maladaptive coping strategies dimension predicted the SPQ compulsive buying, binge eating and food restriction subscales. The latent dimensions significantly correlated with each other. Compulsive sex might be preliminarily considered as a behavioral addiction. AUD individuals might show complex patterns of maladaptive behaviors functionally related to different latent processes. Differential treatment approaches are suggested to treat these conditions.

Exploration of Intervention Strategies to Reduce Public Stigma Associated with Gambling Disorder

Stigma associated with gambling disorder is complex, and is a key obstacle that prevents sufferers from seeking early help for their condition. However, little research has addressed how best to reduce gambling stigma. This study explored the effectiveness of video intervention styles, that have been used to reduce public stigma for conditions such as mental illness and substance use disorders. This was done to determine which would be most suitable, considering the unique characteristics of gambling disorder. An online survey of 164 people living in Australia was conducted which examined attitudes toward gamblers experiencing problems before and after an intervention. Participants were randomly allocated to one of three interventions (contact, education, advocacy) or a control video. The study found that each intervention was associated with changes to different components of stigma. Importantly, the education intervention increased labelling, but reduced stereotype endorsement and anger. Advocacy also reduced anger, attributions of character flaws, and anticipated discrimination and recoverability. While these interventions were generally effective at reducing stigma, the contact intervention was mixed, effectively intervening for some aspects of stigma, but increasing stigma on others. No single intervention reduced all aspects of stigma, suggesting that a complementary approach utilising specific elements of each intervention style could be used to deliver relevant information and effectively reduce stigma. Taken together, this suggests that research should be conducted into comprehensive, combined interventions, that include aspects of all three intervention styles, in an attempt to reduce more aspects of stigma simultaneously.

Treating gambling disorder with as needed administration of intranasal naloxone: a pilot study to evaluate acceptability, feasibility and outcomes

BACKGROUND AND AIM

There is growing interest in the use of medication-assisted treatments for gambling disorder (GD). Opioid receptor antagonists are hypothesised to blunt the craving associated with gambling. This study was designed to assess the feasibility of using an intranasal naloxone spray to treat GD.

DESIGN

An 8-week, open-label, uncontrolled pilot study.

SETTING

A single study site in the capital region of Finland.

SUBJECTS

Twenty problem gamblers (nine men) were randomised into two groups. Group A (n=10) took one dose into one nostril (2 mg naloxone), as needed, with a maximum of 4 doses/day (max. 8 mg/day). Group B (n=10) took one dose into each nostril (4 mg naloxone) as needed, with a maximum of 4 doses/day (max. 16 mg/day).

INTERVENTION

Naloxone hydrochloride nasal spray.

MEASURES

Acceptability and feasibility of the intervention were assessed. Use of study medication, adverse events, gambling frequency and gambling expenditure were recorded in a mobile diary. Problem gambling: South Oaks Gambling Screen (SOGS), depressive symptoms: Beck Depression Inventory (BDI) and alcohol use: Alcohol Use Disorders Identification Test were recorded.

RESULTS

Study completion rate was 90%. Acceptability and feasibility scores were high. Group B used intranasal naloxone more frequently than group A, and consequently used more naloxone. No serious adverse events were reported. The postintervention SOGS scores were lower (median=4 (IQR=3.75) versus preintervention scores (median=12 (IQR=4.75)). Depressive symptoms were reduced during the trial (preintervention BDI median=9, IQR=9 vs postintervention BDI median=6, IQR=6).

CONCLUSIONS

The acceptability and feasibility of using intranasal naloxone were high, and no serious adverse events were reported. Preliminary results suggest mixed results in terms of gambling behaviour (ie, reduced frequency but not expenditure) and decreased depressive symptoms.

TRIAL REGISTRATION NUMBER

EudraCT2016-001828-56.

Diagnostic and Classification Considerations Regarding Gaming Disorder: Neurocognitive and Neurobiological Features

Video gaming and Internet use have become a part of the everyday lives of many individuals, especially during adolescence. Given the health concerns related to problematic gaming behaviors, gaming disorder (GD) has been included in the version of the 11th edition of The International Classification of Diseases (ICD-11) ratified by the secretariat of the World Health Organization. Given these considerations and others (including debate regarding the most appropriate classification of GD and how best to prevent and treat the condition), there is a need for further research into GD. Specifically, we suggest that researching intermediate phenotypes focusing on cognitive and neurobiological function may help clarify GD's relationships to other addictive disorders and more accurately define their relationships with core and associated features of GD. Overlaps in neural activity, cognitive functioning, and other features suggest that GD shares similarities with gambling and substance-use disorders and may best be classified as an addictive disorder. Individuals with GD differ from those with regular game use (RGU) on neurocognitive levels. However, concerns have been raised with respect to the differences between GD and substance-use disorders in certain dimensional features, such as tolerance. Additionally, it has been argued that differences between GD and RGU may not be fully captured by nomenclature systems like the ICD-11. Nonetheless, individuals seek treatment for help with GD, despite the limited data available for effective treatments. As more data are gathered from investigations of GD, they should be translated into refining criteria for GD and optimizing interventions.

Developmental trajectories of gambling severity after cognitive-behavioral therapy

AIMS

To estimate trajectories of the gambling disorder (GD) severity for 12 months following a manualized cognitive-behavior-therapy (CBT) program, and to identify the main variables associated with each trajectory.

METHODS

Latent Class Growth Analysis examined the longitudinal changes of n = 603 treatment-seeking patients with GD.

RESULTS

Five separate empirical trajectories were identified: T1 (n = 383, 63.5%) was characterized by the most highest baseline gambling severity levels and positive progress to recovery during the follow-up period; T2 (n = 154, 25.5%) featured participants with high baseline gambling severity and good progress to recovery; T3 (n = 30, 5.0%) was made up of patients with high gambling baseline severity and slow progress to recovery; T4 (n = 13, 2.2%) and T5 (n = 23, 3.8%) contained participants with high baseline gambling severity and moderate (T4) and poor (T5) progress in GD severity during the follow-up. Psychopathological state and personality traits discriminated between trajectories. Poor compliance with the therapy guidelines and the presence of relapses also differed between the trajectories.

CONCLUSIONS

Our findings show that patients seeking treatment for GD are heterogeneous and that trends in progress following treatment can be identified considering sociodemographic features, psychopathological state and personality traits. These results could be useful in developing more efficient interventions for GD patients.

Internet Gaming Disorder in Adolescents With Psychiatric Disorder: Two Case Reports Using a Developmental Framework

Internet gaming disorder (IGD) has been a controversial entity with various opinions about its clinical relevance as an independent mental disorder. This debate has also included discussions about the relationships between problematic gaming, various psychiatric disorders, and personality traits and dimensions. This paper outlines a developmental-theory based model of Internet gaming misuse inspired by the treatment of two adolescent inpatients. The two clinical vignettes illustrate distinct developmental pathways: an "internalized pathway" via the development of social anxiety, emotional and behavioral avoidance; and an "externalized pathway" with a low level of emotional regulation strategies and impulsivity. In both clinical cases, attachment issues played a key role to understand the specific associations of risk and maintaining factors for IGD, and gaming behaviors may be seen as specific forms of maladaptive self-regulatory strategies for these two youths. These clinical observations support the assumption that gaming use problematic in adolescents should be viewed with a developmental approach, including key aspects of emotional development that represent significant targets for therapeutic interventions.

Prenatal cannabinoid exposure and altered neurotransmission

Marijuana is one of the most commonly used illicit drugs worldwide. In addition, use of synthetic cannabinoids is increasing, especially among adolescents and young adults. Although human studies have shown that the use of marijuana during pregnancy leads to adverse behavioral effects, such as deficiencies in attention and executive function in affected offspring, the rate of marijuana use among pregnant women is steadily increasing. Various aspects of human behavior including emotion, learning, and memory are dependent on complex interactions between multiple neurotransmitter systems that are especially vulnerable to alterations during the developmental period. Thus, exploration of neurotransmitter changes in response to prenatal cannabinoid exposure is crucial to develop an understanding of how homeostatic imbalance and various long-term neurobehavioral deficits manifest following the abuse of marijuana or other synthetic cannabinoids during pregnancy. Current literature confirms that vast alterations to neurotransmitter systems are present following prenatal cannabinoid exposure, and many of these alterations within the brain are region specific, time-dependent, and sexually dimorphic. In this review, we aim to provide a summary of observed changes to various neurotransmitter systems following cannabinoid exposure during pregnancy and to draw possible correlations to reported behavioral alterations in affected offspring.

Workaholism, Motivation, and Addiction in the Workplace: A Critical Review and Implications for HRD

Despite the wide use of the term workaholism, universally defined as an addiction to work, there is little consensus on this concept and how people become workaholics. This article critically reviews the workaholism literature to reframe the concept of workaholism and to provide implications for human resource development (HRD). Through a literature review, four perspectives were found based on assumptions about behavioral motivation. The motivation and addiction processes in workaholism are discussed, focusing on the theories and characteristics of the workplace. The gaps and omissions are identified in the reviewed research, and a workaholism framework is suggested that emphasizes contextual and behavioral inclusiveness. This review contributes to literature on workaholism by illuminating current divergent opinions on workaholism and guiding future research. The recommendations can also enhance the practical development of individuals and organizations that currently or potentially face excessive work issues.

Exposure to conditions of uncertainty promotes the pursuit of amphetamine

Prior exposure to abused drugs leads to long-lasting neuroadaptations culminating in excessive drug intake. Given the comorbidity between substance use and gambling disorders, surprisingly little is known about the effects of exposure to reinforcement contingencies experienced during games of chance. As it is a central feature of these games, we characterized the effects of exposure to uncertainty on biochemical and behavioral effects normally observed in rats exposed to amphetamine. Rats in different groups were trained to nose-poke for saccharin under certain [fixed-ratio (FR)] or uncertain conditions [variable-ratio (VR)] for 55 1-h sessions. Ratios were escalated on successive sessions and rats maintained on the last ratio (FR/VR 20) for 20-25 days. Two to three weeks later, rats were tested for their locomotor or nucleus accumbens dopamine (NAcc DA) response to amphetamine or self-administration of the drug using a lever press operant. NAcc DA overflow was also assessed in additional rats during the saccharin sessions. Rats exposed to uncertainty subsequently showed a higher locomotor and NAcc DA response to amphetamine and self-administered more drug infusions relative to rats exposed to predictable reinforcement. NAcc DA levels during the saccharin sessions tracked the variance of the scheduled ratios (a measure of uncertainty). VR rats showed escalating DA overflow with increasing ratios. Exposure to uncertainty triggered neuroadaptations similar to those produced by exposure to abused drugs. As these were produced in drug naive rats both during and after exposure to uncertainty, they provide a novel common pathway to drug and behavioral addictions.

Pathways Relating the Neurobiology of Attachment to Drug Addiction

Substance use disorders constitute a significant public health problem in North America and worldwide. Specifically, substance addictions in women during pregnancy or in the postpartum period have adverse effects not only on the mother, but also on mother-infant attachment and the child's subsequent development. Additionally, there is growing evidence suggesting that parental addiction may be transmitted intergenerationally, where the child of parents with addiction problems is more likely to experience addiction as an adult. The current review takes a developmental perspective and draws from animal and human studies to examine how compromised early experience, including insecure attachment, early abuse/neglect, and unresolved trauma, may influence the development of neurobiological pathways associated with addictions, ultimately increasing one's susceptibility to addictions later in life. We approach this from three different levels: molecular, neuroendocrine and behavioral; and examine the oxytocin affiliation system, dopamine reward system, and glucocorticoid stress response system in this regard. Increased understanding of these underlying mechanisms may help identify key targets for early prevention efforts and inform needed intervention strategies related to both insecure attachment and addiction.

Trait impulsivity and cognitive domains involving impulsivity and compulsivity as predictors of gambling disorder treatment response

BACKGROUND AND AIMS

Gambling disorder (GD) is a highly heterogeneous condition with high rates of chronicity, relapses and treatment dropout. The aim of this study was to longitudinally explore the associations between trait impulsivity, impulsivity-compulsivity related cognitive domains, and treatment outcome in an outpatient sample of adult patients with GD.

METHODS

144 adult male participants diagnosed with GD undergoing cognitive-behavioural treatment (CBT) at a specialized outpatient service completed a series of neuropsychological tests to assess executive functioning (including cognitive flexibility, inhibition control and decision making) and psychometric questionnaires.

RESULTS

Trait impulsivity predicted low compliance [UPPS-P negative urgency (B = 0.113; p = 0.019)] and relapse [UPPS-P negative urgency (B = 0.140; p = 0.015)] at 5 weeks of treatment and dropout at the end of treatment [(UPPS-P sensation seeking B = 0.056; p = 0.045)]. Cognitive flexibility performance predicted: dropout rates at the end of treatment [WCST perseverative errors (B = 0.043; p = 0.042)]; dropout [WCST categories completed (B = -1.827; p = 0.020)] and low compliance or relapses at follow-up [WCST perseverative errors (B = 0.128; p = 0.020)]; and time to first relapse [WCST failure to maintain set (B = -0.374; p = 0.048)] and time to dropout [WCST perseverative errors (B = 0.0198; p = 0.019)].

CONCLUSIONS

Our findings indicate impulsivity-compulsivity levels may influence response to GD treatment (i.e.: low compliance and dropout or relapse rates) thus representing a potential target for improving treatment outcomes.

Cognitive training: A new avenue in gambling disorder management?

INTRODUCTION

Cognitive deficits are being robustly documented in gambling disorder. Cognitive training has been increasingly investigated as a treatment of substance use disorders. Four training components have been listed to date: cognitive bias, response inhibition, working memory, and goal-directed. This review aimed at the identification of use and efficacy findings in cognitive training in gambling disorder.

METHODS

We conducted a systematic search to identify use and efficacy data of cognitive training in gambling disorder. No use or efficacy data was available.

DISCUSSION AND PERSPECTIVES

Studies assessing cognitive training in gambling disorder are being conducted and first results should be upcoming. Methodological challenges have been identified. Several candidate target cognitive functions of training programs are being investigated, relying on the most documented impairments in gambling disorder, inhibition, reward sensitivity and decision making. Gambling-specific or neutral environments are to be distinguished clearly and do not rely on similar assumptions, i.e. general vulnerability or vulnerability expressed only in the specific context of gambling. Proper control groups with placebo conditions should be implemented. Assessment of efficacy should include clinical and neuropsychological assessments to give information of underlying mechanisms of action.

Animal models in addiction research: A dimensional approach

Drug addiction affects approximately 10% of the population and these numbers are rising. Treatment and prevention of addiction are impeded by current diagnostic systems, such as DSM-5, which are based on outcomes rather than processes. Here, we review the importance of adopting a dimensional framework, specifically the Research Domain Criteria (RDoC), to identify protective and vulnerability mechanisms in addiction. We discuss how preclinical researchers should work within this framework to develop animal models based on domains of function. We highlight RDoC paradigms related to addiction and discuss how these can be used to investigate the biological underpinnings of an addiction cycle (i.e., binge/intoxication, negative affect, and craving). Using this information, we then outline the critical role of animal research in ongoing revisions to the RDoC matrix (specifically the functional significance of domains, constructs and subconstructs) and its contribution to the development and refinement of addiction theories. We conclude with an overview of the contribution that animal research has made to the development of pharmacological and behavioural treatments for addiction.

Internet gaming disorder in children and adolescents: a systematic review

AIM

Internet gaming disorder (IGD) is a serious disorder leading to and maintaining pertinent personal and social impairment. IGD has to be considered in view of heterogeneous and incomplete concepts. We therefore reviewed the scientific literature on IGD to provide an overview focusing on definitions, symptoms, prevalence, and aetiology.

METHOD

We systematically reviewed the databases ERIC, PsyARTICLES, PsycINFO, PSYNDEX, and PubMed for the period January 1991 to August 2016, and additionally identified secondary references.

RESULTS

The proposed definition in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition provides a good starting point for diagnosing IGD but entails some disadvantages. Developing IGD requires several interacting internal factors such as deficient self, mood and reward regulation, problems of decision-making, and external factors such as deficient family background and social skills. In addition, specific game-related factors may promote IGD. Summarizing aetiological knowledge, we suggest an integrated model of IGD elucidating the interplay of internal and external factors.

INTERPRETATION

So far, the concept of IGD and the pathways leading to it are not entirely clear. In particular, long-term follow-up studies are missing. IGD should be understood as an endangering disorder with a complex psychosocial background.

WHAT THIS PAPER ADDS

In representative samples of children and adolescents, on average, 2% are affected by Internet gaming disorder (IGD). The mean prevalences (overall, clinical samples included) reach 5.5%. Definitions are heterogeneous and the relationship with substance-related addictions is inconsistent. Many aetiological factors are related to the development and maintenance of IGD. This review presents an integrated model of IGD, delineating the interplay of these factors.

Closed Loop Deep Brain Stimulation for PTSD, Addiction, and Disorders of Affective Facial Interpretation: Review and Discussion of Potential Biomarkers and Stimulation Paradigms

The treatment of psychiatric diseases with Deep Brain Stimulation (DBS) is becoming more of a reality as studies proliferate the indications and targets for therapies. Opinions on the initial failures of DBS trials for some psychiatric diseases point to a certain lack of finesse in using an Open Loop DBS (OLDBS) system in these dynamic, cyclical pathologies. OLDBS delivers monomorphic input into dysfunctional brain circuits with modulation of that input via human interface at discrete time points with no interim modulation or adaptation to the changing circuit dynamics. Closed Loop DBS (CLDBS) promises dynamic, intrinsic circuit modulation based on individual physiologic biomarkers of dysfunction. Discussed here are several psychiatric diseases which may be amenable to CLDBS paradigms as the neurophysiologic dysfunction is stochastic and not static. Post-Traumatic Stress Disorder (PTSD) has several peripheral and central physiologic and neurologic changes preceding stereotyped hyper-activation behavioral responses. Biomarkers for CLDBS potentially include skin conductance changes indicating changes in the sympathetic nervous system, changes in serum and central neurotransmitter concentrations, and limbic circuit activation. Chemical dependency and addiction have been demonstrated to be improved with both ablation and DBS of the Nucleus Accumbens and as a serendipitous side effect of movement disorder treatment. Potential peripheral biomarkers are similar to those proposed for PTSD with possible use of environmental and geolocation based cues, peripheral signs of physiologic arousal, and individual changes in central circuit patterns. Non-substance addiction disorders have also been serendipitously treated in patients with OLDBS for movement disorders. As more is learned about these behavioral addictions, DBS targets and effectors will be identified. Finally, discussed is the use of facial recognition software to modulate activation of inappropriate responses for psychiatric diseases in which misinterpretation of social cues feature prominently. These include Autism Spectrum Disorder, PTSD, and Schizophrenia-all of which have a common feature of dysfunctional interpretation of facial affective clues. Technological advances and improvements in circuit-based, individual-specific, real-time adaptable modulation, forecast functional neurosurgery treatments for heretofore treatment-resistant behavioral diseases.

Focusing on the Opioid System for Addiction Biomarker Discovery

Substance use disorders (SUD) and behavioral addictions are devastating conditions that impose a severe burden on all societies, and represent difficult challenges for clinicians. Therefore, biomarkers are urgently needed to help predict vulnerability, clinical course, and response to treatment. Here, we elaborate on the potential for addiction biomarker discovery of the opioid system, particularly within the emerging framework aiming to probe opioid function in peripheral tissues. Mu, delta, and kappa opioid receptors all critically regulate neurobiological and behavioral processes that define addiction, and are also targeted by major pharmacotherapies used in the management of patients with SUD. We propose that opioid biomarkers may have the potential to improve and guide diagnosis and therapeutic decisions in the addiction field.

Validation of the Spanish Version of the Yale Food Addiction Scale 2.0 (YFAS 2.0) and Clinical Correlates in a Sample of Eating Disorder, Gambling Disorder, and Healthy Control Participants

Aims: Due to the increasing evidence of shared vulnerabilities between addictive behaviors and excessive food intake, the concept of food addiction in specific clinical populations has become a topic of scientific interest. The aim of this study was to validate the Yale Food Addiction Scale (YFAS) 2.0 in a Spanish sample. We also sought to explore food addiction and its clinical correlates in eating disorder (ED) and gambling disorder (GD) patients. Methods: The sample included 301 clinical cases (135 ED and 166 GD), diagnosed according to DSM-5 criteria, and 152 healthy controls (HC) recruited from the general population. Results: Food addiction was more prevalent in patients with ED, than in patients with GD and HC (77.8, 7.8, and 3.3%, respectively). Food addiction severity was associated with higher BMI, psychopathology and specific personality traits, such as higher harm avoidance, and lower self-directedness. The psychometrical properties of the Spanish version of the YFAS 2.0 were excellent with good convergent validity. Moreover, it obtained good accuracy in discriminating between diagnostic subtypes. Conclusions: Our results provide empirical support for the use of the Spanish YFAS 2.0 as a reliable and valid tool to assess food addiction among several clinical populations (namely ED and GD). The prevalence of food addiction is heterogeneous between disorders. Common risk factors such as high levels of psychopathology and low self-directedness appear to be present in individuals with food addiction.

Psychopathology of addiction: Can the SCL90-based five-dimensional structure differentiate Heroin Use Disorder from a non-substance-related addictive disorder such as Gambling Disorder?

BACKGROUND

In the Gambling Disorder (GD), there is no exogenous drug administration that acts as the central core of the traditional meaning of addiction. A specific psychopathology of Substance Use Disorders has been proposed recently. In a sample of Heroin Use Disorder (HUD) patients entering opioid agonist treatment, it became possible to identify a group of 5 mutually exclusive psychiatric dimensions: Worthlessness-Being trapped (W-BT), Somatic Symptoms (SS), Sensitivity-Psychoticism (SP), Panic Anxiety (PA) and Violence-Suicide (VS). The specificity of these dimensions was suggested by the absence of their correlations with treatment choice, active substance use, psychiatric comorbidity and the principal substance of abuse and by the opportunity, through their use, of fully discriminating HUD from Major Depression patients and, partially, from obese non-psychiatric patients. To further support this specificity in the present study, we tested the feasibility of discriminating HUD patients from those affected by a non-substance-related addictive behaviour, such as GD. In this way, we also investigated the psychopathological peculiarities of GD patients.

METHODS

We compared the severity and frequency of each of the five aspects found by us, in 972 (83.5% males; mean age 30.12 ± 6.6) HUD and 110 (50% males; average age 30.12 ± 6.6) GD patients at univariate (T test; Chi square) and multivariate (discriminant analysis and logistic regression) level.

RESULTS

HUD patients showed higher general psychopathology indexes than GD patients. The severity of all five psychopathological dimensions was significantly greater in HUD patients. Discriminant analysis revealed that SS and VS severity were able to discriminate between HUD (higher severity) and GD patients (lower severity), whereas PA and SP could not. W-BT severity was negatively correlated with SS and VS; GD patients were distinguished by low scores for SS and VS low scores associated with high ones for W-BT. Psychopathological subtypes characterized by SS and VS symptomatology were better represented in HUD patients, whereas PA symptomatology was more frequent in GD individuals. No differences were observed regarding the W-BT and SP dimensions. At multivariate level, the one prominent characteristic of HUD patients was the presence of SS (OR = 5.43) as a prominent qualification for psychopathological status.

CONCLUSIONS

Apart from the lower severity of all psychopathological dimensions, only the lower frequency of SS typology seems to be the prominent factor in GD patients. The SCL90-defined structure of opioid addiction seems to be useful even in non-substance-related addictive disorders, as in the case of GD patients, further supporting the possible existence of a psychopathology specific to addiction.

Beneficial and detrimental effects of genetic explanations for addiction

BACKGROUND

Addictions are highly stigmatized and increasingly construed as biomedical diseases caused by genes, partly to reduce stigma by deflecting blame. However, genetic explanations may have negative effects, which have been understudied in the context of addiction. How the effects of genetic explanations might differ for substance addictions versus behavioral addictions is also unknown.

AIMS

This study examined the impact of genetic explanations for addiction on measures of treatment expectancies, blame, and perceived agency and self-control, as well as whether these varied depending on whether the addiction was to a substance or a behavior.

METHODS

Participants read about a person ('Charlie') with either alcohol use disorder or gambling disorder, receiving either a genetic or nongenetic explanation of Charlie's problem. They rated how much they blamed Charlie for his disorder, his likelihood of benefitting from medication or psychotherapy, and how much agency and self-control they ascribed to him.

RESULTS

Compared to the nongenetic explanation, the genetic explanation reduced blame and increased confidence in the effectiveness of pharmacotherapy. However, it also decreased the expected effectiveness of psychotherapy and reduced ascriptions of agency and self-control.

CONCLUSION

Genetic explanations for addiction appear to be a 'double-edged sword', with beneficial effects that come at a cost.

Deriving low-risk gambling limits from longitudinal data collected in two independent Canadian studies

AIMS

To derive low-risk gambling limits using the method developed by Currie et al. (2006) applied to longitudinal data.

DESIGN

Secondary analysis of data from the Quinte Longitudinal Study (n = 3054) and Leisure, Lifestyle and Lifecycle Project (n = 809), two independently conducted cohort studies of the natural progression of gambling in Canadian adults.

SETTING

Community-dwelling adults in Southeastern Ontario and Alberta, Canada.

PARTICIPANTS

A total of 3863 adults (50% male; median age = 44) who reported gambling in the past year.

MEASUREMENTS

Gambling behaviours (typical monthly frequency, total expenditure and percentage of income spent on gambling) and harm (experiencing two or more consequences of gambling in the past 12 months) were assessed with the Canadian Problem Gambling Index.

FINDINGS

The dose-response relationship was comparable in both studies for frequency of gambling (days per month), total expenditure and percentage of household income spent on gambling (area under the curve values ranged from 0.66 to 0.74). Based on the optimal sensitivity and specificity values, the low-risk gambling cut-offs were eight times per month, $75CAN total per month and 1.7% of income spent on gambling. Gamblers who exceeded any of these limits at time 1 were approximately four times more likely to report harm at time 2 [95% confidence interval (CI) = 2.9-6.6].

CONCLUSIONS

Longitudinal data in Canada suggest low-risk gambling thresholds of eight times per month, $75CAN total per month and 1.7% of income spent on gambling, all of which are higher than previously derived limits from cross-sectional data. Gamblers who exceed any of the three low-risk limits are four times more likely to experience future harm than those who do not.

Poor sleep quality and suicide attempt among adults with internet addiction: A nationwide community sample of Korea

Purpose

Internet addiction (IA) is defined as a psychological dependence on the internet, regardless of the type of activities once logged on, and previous studies have focused on adolescents and young adults. The aim of this study was to investigate the association between suicide attempts and sleep among community-dwelling adults with IA.

Methods

The Young’s Internet Addiction Test (IAT), the Korean version of the Composite International Diagnostic Interview (K-CIDI) and a suicide questionnaire were used in this cross-sectional multistage, cluster sampling population-based study. A total of 3212 adults aged 18–64 years were interviewed face-to-face, and they had been randomly selected through a one-person-per-household method.

Results

Of the 3212 adults, 204 were assessed as having IA (6.35%). Adults with IA were younger, and more frequently male, unmarried, and unemployed, and had poorer sleep quality than adults without IA (32.8% vs. 19.8%), whereas there was no significant difference in the absolute duration of sleep between the two groups. Adults with IA showed more frequent difficulty initiating and maintaining sleep, non-restorative sleep, daytime functional impairment, and duration of sleep more than 10 hours on weekdays than adults without IA. IA with poor sleep quality was significantly associated with lifetime suicide attempts (AOR = 3.34, 95% CI 1.38–8.05) after adjusting for demographic covariates. Adults with IA who had more sleep problems showed more severe IA, especially those who experienced a previous suicidal attempt. Among mental disorders, IA with poor sleep quality was significantly associated with anxiety disorder and overall psychiatric disorders.

Conclusions

Among adults with IA, poor sleep quality was found to be associated with more severe IA and lifetime suicide attempt.

Food Addiction in Gambling Disorder: Frequency and Clinical Outcomes

Background: The food addiction (FA) model is receiving increasing interest from the scientific community. Available empirical evidence suggests that this condition may play an important role in the development and course of physical and mental health conditions such as obesity, eating disorders, and other addictive behaviors. However, no epidemiological data exist on the comorbidity of FA and gambling disorder (GD), or on the phenotype for the co-occurrence of GD+FA.

Objectives: To determine the frequency of the comorbid condition GD+FA, to assess whether this comorbidity features a unique clinical profile compared to GD without FA, and to generate predictive models for the presence of FA in a GD sample.

Method: Data correspond to N = 458 treatment-seeking patients who met criteria for GD in a hospital unit specialized in behavioral addictions.

Results: Point prevalence for FA diagnosis was 9.2%. A higher ratio of FA was found in women (30.5%) compared to men (6.0%). Lower FA prevalence was associated with older age. Patients with high FA scores were characterized by worse psychological state, and the risk of a FA diagnosis was increased in patients with high scores in the personality traits harm avoidance and self-transcendence, and low scores in cooperativeness (R² = 0.18).

Conclusion: The co-occurrence of FA in treatment-seeking GD patients is related to poorer emotional and psychological states. GD treatment interventions and related behavioral addictions should consider potential associations with problematic eating behavior and aim to include techniques that aid patients in better managing this behavior.

Dopamine and Opioid Neurotransmission in Behavioral Addictions: A Comparative PET Study in Pathological Gambling and Binge Eating

Although behavioral addictions share many clinical features with drug addictions, they show strikingly large variation in their behavioral phenotypes (such as in uncontrollable gambling or eating). Neurotransmitter function in behavioral addictions is poorly understood, but has important implications in understanding its relationship with substance use disorders and underlying mechanisms of therapeutic efficacy. Here, we compare opioid and dopamine function between two behavioral addiction phenotypes: pathological gambling (PG) and binge eating disorder (BED). Thirty-nine participants (15 PG, 7 BED, and 17 controls) were scanned with [¹¹C]carfentanil and [¹⁸F]fluorodopa positron emission tomography using a high-resolution scanner. Binding potentials relative to non-displaceable binding (BP_ND) for [¹¹C]carfentanil and influx rate constant (K_i) values for [¹⁸F]fluorodopa were analyzed with region-of-interest and whole-brain voxel-by-voxel analyses. BED subjects showed widespread reductions in [¹¹C]carfentanil BP_ND in multiple subcortical and cortical brain regions and in striatal [¹⁸F]fluorodopa K_i compared with controls. In PG patients, [¹¹C]carfentanil BP_ND was reduced in the anterior cingulate with no differences in [¹⁸F]fluorodopa K_i compared with controls. In the nucleus accumbens, a key region involved in reward processing, [¹¹C]Carfentanil BP_ND was 30-34% lower and [¹⁸F]fluorodopa K_i was 20% lower in BED compared with PG and controls (p<0.002). BED and PG are thus dissociable as a function of dopaminergic and opioidergic neurotransmission. Compared with PG, BED patients show widespread losses of mu-opioid receptor availability together with presynaptic dopaminergic defects. These findings highlight the heterogeneity underlying the subtypes of addiction and indicate differential mechanisms in the expression of pathological behaviors and responses to treatment.

The role of affect-driven impulsivity in gambling cognitions: A convenience-sample study with a Spanish version of the Gambling-Related Cognitions Scale

Background and aims Abnormal cognitions are among the most salient domain-specific features of gambling disorder. The aims of this study were: (a) to examine and validate a Spanish version of the Gambling-Related Cognitions Scale (GRCS; Raylu & Oei, 2004) and (b) to examine associations between cognitive distortion levels, impulsivity, and gambling behavior. Methods This study first recruited a convenience sample of 500 adults who had gambled during the previous year. Participants were assessed using the Spanish version of GRCS (GRCS-S) questionnaire, the UPPS-P impulsivity questionnaire, measures of gambling behavior, and potentially relevant confounders. Robust confirmatory factor analysis methods on half the sample were used to select the best models from a hypothesis-driven set. The best solutions were validated on the other half, and the resulting factors were later correlated with impulsivity dimensions (in the whole n = 500 factor analysis sample) and clinically relevant gambling indices (in a separate convenience sample of 137 disordered and non-disordered gamblers; validity sample). Results This study supports the original five-factor model, suggests an alternative four-factor solution, and confirms the psychometric soundness of the GRCS-S. Importantly, cognitive distortions consistently correlated with affect- or motivation-driven aspects of impulsivity (urgency and sensation seeking), but not with cognitive impulsivity (lack of premeditation and lack of perseverance). Discussion and conclusions Our findings suggest that the GRCS-S is a valid and reliable instrument to identify gambling cognitions in Spanish samples. Our results expand upon previous research signaling specific associations between gambling-related distortions and affect-driven impulsivity in line with models of motivated reasoning.

Problematic alcohol use and problem gambling: Associations to structural and functional aspects of social ties in a Finnish population sample

Aims

This study aims to explore associations between structural and functional aspects of social networks and relationships (here labelled social ties) among individuals exhibiting problematic alcohol use and problem gambling, respectively.

Material & Methods

Data was collected in the 2011 Western Finland Mental Health Survey, a postal questionnaire survey applying a stratified random sampling approach. The survey response rate was 46.2% (n = 4624, age range 15–80 years). Problem behaviours were assessed using the CAGE and Lie/Bet tools. Logistic regression analyses were performed, with problematic alcohol use and problem gambling as dependent variables. Demographic variables, structural social tie factors (marital status, frequency of social contacts, engagement in association activities) and functional social tie factors (experienced loneliness, social support, neighbourhood trust, general trust) constituted explanatory variables.

Results

In this representative population sample, only one structural social tie variable, marital status, proved to be significantly associated with one of the outcomes (problematic alcohol use). Identical functional social tie variables were associated with both problematic alcohol use and problem gambling: individuals exhibiting the problem behaviours experienced higher levels of experienced loneliness and low levels of neighbourhood trust. Identified interaction effects with demographic factors highlight the complexity of links.

Conclusions

Functional aspects of individual-level social ties appear to be more relevant when studying problematic alcohol use or problem gambling, similarly to other forms of mental health problems. The role of social ties as preventive or risk factors for problem behaviour development, as a part of problem behaviour maintenance or as a cessation and a recovery resource should be further explored, considering also interactions with demographic variables.

Treatment modalities for patients with gambling disorder

BACKGROUND

Gambling disorder (GD) is defined as persistent and recurrent problematic gambling behavior leading to clinically significant impairment or distress. The prevalence of GD has been shown to be 1.2-7.1% in the general population. GD can severely impact on personal and vocational wellbeing as well as lead to financial problems, and has been known to be difficult to treat. This review describes the available pharmacotherapy/psychosocial treatments for GD patients, and summarizes data on the effectiveness of these GD treatments.

METHODS

This review refers to newly as well as previously published studies and guidelines.

RESULTS

The description of pharmacotherapy mainly focuses on opioid receptor antagonists, selective serotonin reuptake inhibitors, and mood stabilizers. Psychosocial treatments/strategies mainly include cognitive behavioral therapy, motivational interviewing, and Gamblers Anonymous. We also introduce relatively novel treatment modalities.

CONCLUSIONS

This review can help clinicians to decide treatment plans for their GD patients. In addition, it can be used as a reference for designing future research.

Using two web-based addiction Stroops to measure the attentional bias in adults with Internet Gaming Disorder

Background and aims People with substance abuse and pathological gamblers show an attentional bias. In a laboratory setting, we found an attentional bias using an addiction Stroop in adults with Internet Gaming Disorder (IGD). We aimed at investigating this effect using two web-based experiments. Methods Study 1: Gamers with IGD, casual gamers, and non-gamers (N = 81, 28.1 ± 7.8 years) completed a web-based addiction Stroop with a fully randomized word order. They saw computer-related and neutral words in four colors and indicated the word color via keypress. Study 2: Gamers with IGD, casual gamers, and non-gamers (N = 87, 23.4 ± 5.1 years) completed a web-based addiction Stroop and a classical Stroop (incongruent color and neutral words), which both had a block design. We expected that in both studies, only the gamers with IGD would react more slowly to computer-related words in the addiction Stroop. All groups were expected to react more slowly to incongruent color words in the classical Stroop. Results In neither study did the gamers with IGD differ in their reaction times to computer-related words compared to neutral words. In Study 2, all groups reacted more slowly to incongruent color words than to neutral words confirming the validity of the online reaction time assessment. Discussion Gamers with IGD did not show a significant attentional bias. IGD may differ from substance abuse and pathological gambling in this respect; alternatively experimenting on the Internet may have introduced error variance that made it harder to detect a bias.

eHealth Intervention for Problematic Internet Use (PIU)

Excessive use of the Internet is considered a problematic behaviour by clinicians and researchers. Cognitive behaviour therapy (CBT) has been advocated for a long time as a treatment approach and has been extended to include family therapy in the recent years. As eTherapy (eHealth) has become an important component in the treatment of many mental health problems, it is prudent to explore the current status of the eHealth approach as an intervention option for this problem. This systematic review aims to examine the current development of online intervention programmes for this particular condition. The PRISMA guidelines for systematic reviews and meta-analysis were employed to conduct the search for literature following a systematic and structured approach. Of the 182 articles screened, three satisfied the selection criteria. Information was extracted and analysed systematically for each study and tabulated. All these studies were pilot studies with small sample sizes. Two of these articles aimed to explore the therapeutic efficacy of newly developed online intervention programmes for Internet addiction (IA) and online gaming addiction. The third article described the design and development of an App for smartphone addiction. The results obtained from this review have provided insight into the on-going development of eHealth interventions as well as the health informatics approaches in offering a possible and practical solution to tackle this growing problem.

The challenge of conducting gambling research

SUMMARY

Responding to the survey of 5580 college students in South India in the study of George et al, the author discusses the universality of addictive gambling and its stereotyped nature. This study, together with work in North America and elsewhere, argues for more research that targets prevalence, risk factors, course, and treatment. The author points out the challenge of conducting research when funding is hard to obtain.

DECLARATION OF INTERESTS

None.

COPYRIGHT AND USAGE

© The Royal College of Psychiatrists 2016. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) license.

Integrating psychological and neurobiological considerations regarding the development and maintenance of specific Internet-use disorders: An Interaction of Person-Affect-Cognition-Execution (I-PACE) model

Within the last two decades, many studies have addressed the clinical phenomenon of Internet-use disorders, with a particular focus on Internet-gaming disorder. Based on previous theoretical considerations and empirical findings, we suggest an Interaction of Person-Affect-Cognition-Execution (I-PACE) model of specific Internet-use disorders. The I-PACE model is a theoretical framework for the processes underlying the development and maintenance of an addictive use of certain Internet applications or sites promoting gaming, gambling, pornography viewing, shopping, or communication. The model is composed as a process model. Specific Internet-use disorders are considered to be the consequence of interactions between predisposing factors, such as neurobiological and psychological constitutions, moderators, such as coping styles and Internet-related cognitive biases, and mediators, such as affective and cognitive responses to situational triggers in combination with reduced executive functioning. Conditioning processes may strengthen these associations within an addiction process. Although the hypotheses regarding the mechanisms underlying the development and maintenance of specific Internet-use disorders, summarized in the I-PACE model, must be further tested empirically, implications for treatment interventions are suggested.

Chronic D2/3 agonist ropinirole treatment increases preference for uncertainty in rats regardless of baseline choice patterns

D_2/3 receptor agonists are effective treatments for Parkinson's disease (PD), but can precipitate impulse control disorders (ICDs) including gambling disorder (GD). The neurobiological mechanisms underlying this devastating side-effect of dopamine agonist replacement therapy (DRT), and any dependence on the dopamine depletion caused by PD, are unclear. It is also unclear whether previous biases towards risk or uncertainty are a risk factor for developing these ICDs. We investigated whether chronic D_2/3 agonist administration (5 mg/kg/day ropinirole for 28 days) altered performance of a rat model of gambling-like behaviour, the rodent betting task (rBT), and examined if baseline behaviour predicted this behavioural change. The rBT captures individual differences in subjective preference for uncertain outcomes: animals choose between guaranteed or probabilistic reinforcement of equal expected value. Chronic ropinirole dramatically increased selection of the uncertain option in two-thirds of animals, regardless of baseline preferences. The effect on choice in the rBT was replicated in a dorsolateral striatal 6-hydroxydopamine (6-OHDA) rat model of early PD. These studies are the first to look at individual differences in response to chronic, rather than pulsatile, dosing of DRT in a rodent model of gambling behaviour. These findings suggest that DRT-induced PG may stem from increases in subjective valuation of uncertainty. Such symptoms likely arise because of changes in dopaminergic striatal signalling caused by DRT rather than from an interaction between pre-morbid behaviours or PD itself.

Neurobiology of addiction: a neurocircuitry analysis

Drug addiction represents a dramatic dysregulation of motivational circuits that is caused by a combination of exaggerated incentive salience and habit formation, reward deficits and stress surfeits, and compromised executive function in three stages. The rewarding effects of drugs of abuse, development of incentive salience, and development of drug-seeking habits in the binge/intoxication stage involve changes in dopamine and opioid peptides in the basal ganglia. The increases in negative emotional states and dysphoric and stress-like responses in the withdrawal/negative affect stage involve decreases in the function of the dopamine component of the reward system and recruitment of brain stress neurotransmitters, such as corticotropin-releasing factor and dynorphin, in the neurocircuitry of the extended amygdala. The craving and deficits in executive function in the so-called preoccupation/anticipation stage involve the dysregulation of key afferent projections from the prefrontal cortex and insula, including glutamate, to the basal ganglia and extended amygdala. Molecular genetic studies have identified transduction and transcription factors that act in neurocircuitry associated with the development and maintenance of addiction that might mediate initial vulnerability, maintenance, and relapse associated with addiction.