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Mestre-Bach G, Potenza MN. Pharmacological management of gambling disorder: an update of the literature. Expert Rev Neurother 2024; 24:391-407. [PMID: 38357896 DOI: 10.1080/14737175.2024.2316833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 02/05/2024] [Indexed: 02/16/2024]
Abstract
INTRODUCTION Gambling disorder (GD) is a mental health condition characterized by persistent and problematic betting behavior. GD generates distress and impairment, and treatment options include psychological and pharmacological interventions. AREAS COVERED This narrative review explores existing pharmacological treatments for GD. The following classes of medications were considered: opioid-receptor antagonists (e.g. naltrexone and nalmefene), serotonin reuptake inhibitors (e.g. fluvoxamine, paroxetine, sertraline, escitalopram, and citalopram), glutamatergic agents (e.g. N-acetylcysteine (NAC), acamprosate, and memantine), mood stabilizers (e.g. topiramate, carbamazepine, lithium), and other medications (e.g. modafinil, nefazodone, olanzapine, haloperidol, tolcapone, and bupropion). EXPERT OPINION Due to the limitations of the studies reviewed, solid conclusions regarding the optimal choice of pharmacotherapy for individuals with GD are challenging to draw at this time. Despite some medications, such as naltrexone and nalmefene, showing promising results, efficacy has varied across studies. The review highlights current gaps/limitations, including small sample sizes, limited diversity in participant demographics, the need for exploring different gambling subtypes and treatment responses, high placebo response rates, lack of longer-term longitudinal information, limited investigation of neurobiological correlates and co-occurring disorders, and the importance of implementation research. Further research is needed to address these gaps and explore additional medications, as well as interventions like neuromodulation.
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Affiliation(s)
- Gemma Mestre-Bach
- Instituto de Investigación, Transferencia e Innovación, Universidad Internacional de La Rioja, La Rioja, Spain
| | - Marc N Potenza
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
- Child Study Center, Yale University School of Medicine, New Haven, CT, USA
- Connecticut Mental Health Center, New Haven, CT, USA
- Connecticut Council On Problem Gambling, Wethersfield, CT, USA
- Department of Neuroscience, Yale University, New Haven, CT, USA
- Wu Tsai Institute, Yale University, New Haven, CT, USA
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Zack M, Lobo D, Biback C, Fang T, Smart K, Tatone D, Kalia A, Digiacomo D, Kennedy JL. Priming effects of a slot machine game and amphetamine on probabilistic risk-taking in people with gambling disorder and healthy controls. J Clin Exp Neuropsychol 2023; 45:31-60. [PMID: 36919514 DOI: 10.1080/13803395.2023.2187041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
INTRODUCTION The Game of Dice Task (GDT) captures probabilistic risk-taking, which is an important feature of addictions and integral to gambling disorder (GD). No research appears to have assessed effects of gambling-specific priming manipulations or the pharmacological basis of such effects on the GDT. AIMS To investigate effects of slot machine gambling (Slots) and d-amphetamine (AMPH; 20 mg) on risk-taking in people with GD and healthy controls (HCs) (n = 30/group). The role of dopamine (DA) was assessed by pre-treating participants with the D2 receptor (D2R)-preferring antagonist, haloperidol (HAL; 3-mg) or mixed D1R-D2R antagonist, fluphenazine (FLU; 3-mg). HYPOTHESES Slots and AMPH will each increase risk-taking based on fewer (less probable) possible outcomes selected (POS) and poorer net monetary outcomes (NMO; gains minus losses) on the GDT, with stronger effects in Group GD. If DA mediates these effects, outcomes will vary with pre-treatment. METHOD Participants attended a pre-experimental baseline session and 4 test sessions. Antagonist Group (HAL, FLU) was manipulated between-participants. Pre-treatment (antagonist, placebo) was manipulated within-participants and counterbalanced over sessions for Slots and AMPH test phases. Moderator/mediator effects of trait and neuropsychological factors and GD severity (South Oaks Gambling Screen; SOGS) were explored via covariance. RESULTS AMPH led to an escalation in risky POS over trial blocks in both groups, regardless of pre-treatment. Cognitive inflexibility (high perseveration-proneness) moderated this effect in Group HC. In Group GD, SOGS selectively predicted riskier POS on AMPH sessions. Group GD achieved poorer NMO vs. Group HC on the pre-experimental baseline and Placebo-Slots sessions. Group HC selectively displayed poorer NMO on the Antagonist-Slots session. CONCLUSIONS The GDT can detect behavioral and pharmacological priming effects. Cognitive inflexibility and symptom severity moderate AMPH-induced risk-taking in HC and GD participants, respectively. Sensitization-related "wanting" of risk may contribute to the latter effect in people with GD.
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Affiliation(s)
- Martin Zack
- Molecular Brain Sciences Research Section, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Daniela Lobo
- Addiction Medicine Service, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Candice Biback
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Tim Fang
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Kelly Smart
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Daniel Tatone
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Aditi Kalia
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Daniel Digiacomo
- Molecular Brain Sciences Research Section, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Addiction Medicine Service, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
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Wolfschlag M, Håkansson A. Drug-Induced Gambling Disorder: Epidemiology, Neurobiology, and Management. Pharmaceut Med 2023; 37:37-52. [PMID: 36611111 PMCID: PMC9825131 DOI: 10.1007/s40290-022-00453-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2022] [Indexed: 01/09/2023]
Abstract
Problematic gambling has been suggested to be a possible consequence of dopaminergic medications used mainly in neurological conditions, i.e. pramipexole and ropinirole, and possibly by one antipsychotic compound, aripiprazole. Patients with Parkinson's disease, restless legs syndrome and other conditions potentially treated with dopamine agonists, as well as patients treated for psychotic disorders, are vulnerable patient groups with theoretically increased risk of developing gambling disorder (GD), for example due to higher rates of mental ill-health in these groups. The aim of the present paper is to review the epidemiological, clinical, and neurobiological evidence of the association between dopaminergic medications and GD, and to describe risk groups and treatment options. The neurobiology of GD involves the reward and reinforcement system, based mainly on mesocorticolimbic dopamine projections, with the nucleus accumbens being a crucial area for developing addictions to substances and behaviors. The addictive properties of gambling can perhaps be explained by the reward uncertainty that activates dopamine signaling in a pathological manner. Since reward-related learning is mediated by dopamine, it can be altered by dopaminergic medications, possibly leading to increased gambling behavior and a decreased impulse control. A causal relationship between the medications and GD seems likely, but the molecular mechanisms behind this association have not been fully described yet. More research is needed in order to fully outline the clinical picture of GD developing in patient groups with dopaminergic medications, and data are needed on the differentiation of risk in different compounds. In addition, very few interventional studies are available on the management of GD induced by dopaminergic medications. While GD overall can be treated, there is need for treatment studies testing the effectiveness of tapering of the medication or other gambling-specific treatment modalities in these patient groups.
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Affiliation(s)
- Mirjam Wolfschlag
- Malmö-Trelleborg Addiction Center, Competence Center Addiction, Region Skåne, Södra Förstadsgatan 35, plan 4, S-205 02 Malmö, Sweden ,Faculty of Medicine, Dept of Clinical Sciences Lund, Lund University, Psychiatry, Lund, Sweden
| | - Anders Håkansson
- Malmö-Trelleborg Addiction Center, Competence Center Addiction, Region Skåne, Södra Förstadsgatan 35, plan 4, S-205 02, Malmö, Sweden. .,Faculty of Medicine, Dept of Clinical Sciences Lund, Lund University, Psychiatry, Lund, Sweden.
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Using pharmacological manipulations to study the role of dopamine in human reward functioning: A review of studies in healthy adults. Neurosci Biobehav Rev 2020; 120:123-158. [PMID: 33202256 DOI: 10.1016/j.neubiorev.2020.11.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 10/30/2020] [Accepted: 11/01/2020] [Indexed: 01/08/2023]
Abstract
Dopamine (DA) plays a key role in reward processing and is implicated in psychological disorders such as depression, substance use, and schizophrenia. The role of DA in reward processing is an area of highly active research. One approach to this question is drug challenge studies with drugs known to alter DA function. These studies provide good experimental control and can be performed in parallel in laboratory animals and humans. This review aimed to summarize results of studies using pharmacological manipulations of DA in healthy adults. 'Reward' is a complex process, so we separated 'phases' of reward, including anticipation, evaluation of cost and benefits of upcoming reward, execution of actions to obtain reward, pleasure in response to receiving a reward, and reward learning. Results indicated that i) DAergic drugs have different effects on different phases of reward; ii) the relationship between DA and reward functioning appears unlikely to be linear; iii) our ability to detect the effects of DAergic drugs varies depending on whether subjective, behavioral, imaging measures are used.
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Zack M, St George R, Clark L. Dopaminergic signaling of uncertainty and the aetiology of gambling addiction. Prog Neuropsychopharmacol Biol Psychiatry 2020; 99:109853. [PMID: 31870708 DOI: 10.1016/j.pnpbp.2019.109853] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 12/03/2019] [Accepted: 12/20/2019] [Indexed: 11/15/2022]
Abstract
Although there is increasing clinical recognition of behavioral addictions, of which gambling disorder is the prototype example, there is a limited understanding of the psychological properties of (non-substance-related) behaviors that enable them to become 'addictive' in a way that is comparable to drugs of abuse. According to an influential application of reinforcement learning to substance addictions, the direct effects of drugs to release dopamine can create a perpetual escalation of incentive salience. This article focusses on reward uncertainty, which is proposed to be the core feature of gambling that creates the capacity for addiction. We describe the neuro-dynamics of the dopamine response to uncertainty that may allow a similar escalation of incentive salience, and its relevance to behavioral addictions. We review translational evidence from both preclinical animal models and human clinical research, including studies in people with gambling disorder. Further, we describe the evidence for 1) the effects of the omission of expected reward as a stressor and to promote sensitization, 2) the effect of the resolution of reward uncertainty as a source of value, 3) structural characteristics of modern Electronic Gaming Machines (EGMs) in leveraging these mechanisms, 4) analogies to the aberrant salience hypothesis of psychosis for creating and maintaining gambling-related cognitive distortions. This neurobiologically-inspired model has implications for harm profiling of other putative behavioral addictions, as well as offering avenues for enhancing neurological, pharmacological and psychological treatments for gambling disorder, and harm reduction strategies for EGM design.
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Affiliation(s)
- Martin Zack
- Centre for Addiction and Mental Health, 33 Russell St, Toronto, ON M5S 2S1, Canada; Department of Pharmacology & Toxicology, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada.
| | - Ross St George
- Department of Psychology, University of British Columbia, Okanagan Campus, 3333 University Way, Kelowna, BC V1V 1V7, Canada.
| | - Luke Clark
- Centre for Gambling Research at UBC, Department of Psychology, University of British Columbia, 2136 West Mall, Vancouver, BC V6T 1Z4, Canada.
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Fugariu V, Zack MH, Nobrega JN, Fletcher PJ, Zeeb FD. Effects of exposure to chronic uncertainty and a sensitizing regimen of amphetamine injections on locomotion, decision-making, and dopamine receptors in rats. Neuropsychopharmacology 2020; 45:811-822. [PMID: 31905371 PMCID: PMC7076035 DOI: 10.1038/s41386-020-0599-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 12/22/2019] [Accepted: 12/30/2019] [Indexed: 02/06/2023]
Abstract
Gambling disorder (GD) is a behavioral addiction that may be linked to alterations in dopamine (DA) systems. Gambling involves chronic exposure to uncertain reward, which can sensitize the activity of DA systems. Here we explored how combinations of Pavlovian and instrumental uncertainty impact DA sensitization and risky decision-making. Experiment 1: 40 rats underwent 66 uncertainty exposure (UE) sessions during which they responded for saccharin. Animal responding was reinforced according to a fixed or variable (FR/VR) ratio schedule that turned on a conditioned stimulus (CS; light), which predicted saccharin on 50% or 100% of trials. Animals responded under one of the four conditions: FR-CS100% (no uncertainty), VR-CS100%, FR-CS50%, and VR-CS50% (maximal uncertainty). DA sensitization was inferred from an enhanced locomotor response to d-amphetamine (d-AMPH; 0.5 mg/kg) challenge. The rat gambling task (rGT) was used to assess decision-making. Experiment 2: 24 rats received 5 weeks of sensitizing d-AMPH or saline doses, followed by locomotor activity and rGT testing. Experiment 3: Effects of UE and a sensitizing d-AMPH regimen on DA D1, D2, and D3 receptor binding were assessed in 44 rats using autoradiography. Compared to FR-CS100%, VR-CS100% and VR-CS50% rats displayed a greater locomotor response to d-AMPH, and VR-CS50% rats demonstrated riskier decision-making. Chronic d-AMPH-treated rats mirrored the effects of VR-CS50% groups on these two indices. Both VR-CS50% and d-AMPH-treated groups had increased striatal DA D2 receptor binding. These results suggest that chronic uncertainty exposure, similar to exposure to a sensitizing d-AMPH regimen, sensitized the function of DA systems and increased risky decision-making.
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Affiliation(s)
- Victoria Fugariu
- Department of Pharmacology & Toxicology, University of Toronto, Toronto, ON, Canada.
- Section of Biopsychology Laboratory, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada.
| | - Martin H Zack
- Department of Pharmacology & Toxicology, University of Toronto, Toronto, ON, Canada
- Molecular Brain Sciences Department, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - José N Nobrega
- Department of Pharmacology & Toxicology, University of Toronto, Toronto, ON, Canada
- Department of Psychology, University of Toronto, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
- Section of Behavioral Neurobiology Laboratory, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Paul J Fletcher
- Section of Biopsychology Laboratory, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychology, University of Toronto, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Fiona D Zeeb
- Section of Biopsychology Laboratory, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
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Abstract
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.
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Affiliation(s)
- Andrew Kayser
- Department of Neurology, Weill Institute for Neurosciences, University of California at San Francisco
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Zack M, Lobo D, Biback C, Fang T, Smart K, Tatone D, Kalia A, Digiacomo D, Kennedy JL. Impulsivity moderates the effects of dopamine D2 and mixed D1-D2 antagonists in individuals with gambling disorder. J Psychopharmacol 2019; 33:1015-1029. [PMID: 31219367 DOI: 10.1177/0269881119855972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND The functional role of dopamine D1 and D2 receptors in gambling disorder (GD) remains unclear. AIMS This study aimed to investigate the role of D1 activation and the moderating effects of impulsivity, a trait linked with weaker D2-mediated inhibition of dopamine release, in GD subjects. METHODS Thirty (nine female) non-comorbid GD subjects with low (LI), moderate (MI), or high impulsivity (HI) received the preferential D2 antagonist haloperidol (HAL; 3 mg) or the mixed D1-D2 antagonist fluphenazine (FLU; 3 mg), on separate sessions before a 15-minute slot machine game or amphetamine (AMPH; 20 mg), in a placebo-controlled, double-blind, counterbalanced design. RESULTS On their own, HAL and FLU led to linear increases and decreases, respectively, in desire to gamble across increasing levels of impulsivity. The slot machine and AMPH each evoked an inverted-U pattern of desire to gamble across increasing impulsivity. HAL reversed this effect of the game, whereas FLU did not alter post-game desire. HAL and FLU decreased and increased psychostimulant-like effects of the game, respectively, in LI and MI subjects, but consistently reduced these effects in HI subjects. HAL also altered the salience of negative affective words on a reading task, such that greater salience of negative words coincided with lower post-game desire to gamble. CONCLUSIONS D1 receptors appear to gauge the incentive value of gambling in GD subjects. D1 activation has negative reinforcing effects in HI gamblers and positive reinforcing effects in LI gamblers. Medications that activate D1 could curtail chasing in HI gamblers. D1 blockade could benefit HI gamblers whose main concern is craving.
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Affiliation(s)
- Martin Zack
- 1 Molecular Brain Sciences Research Department, Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada.,2 Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Daniela Lobo
- 1 Molecular Brain Sciences Research Department, Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada.,3 Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Candice Biback
- 2 Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada.,4 Leslie Dan School of Pharmacy, University of Toronto, Toronto, ON, Canada
| | - Tim Fang
- 2 Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Kelly Smart
- 2 Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Daniel Tatone
- 2 Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Aditi Kalia
- 2 Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Daniel Digiacomo
- 3 Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - James L Kennedy
- 1 Molecular Brain Sciences Research Department, Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada.,3 Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,5 Institute of Medical Science, University of Toronto, Toronto, ON, Canada
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Clark L, Boileau I, Zack M. Neuroimaging of reward mechanisms in Gambling disorder: an integrative review. Mol Psychiatry 2019; 24:674-693. [PMID: 30214041 DOI: 10.1038/s41380-018-0230-2] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 07/28/2018] [Accepted: 08/02/2018] [Indexed: 12/14/2022]
Abstract
Gambling disorder (GD) was reclassified as a behavioral addiction in the DSM-5 and shares clinical and behavioral features with substance use disorders (SUDs). Neuroimaging studies of GD hold promise in isolating core features of the addiction syndrome, avoiding confounding effects of drug neurotoxicity. At the same time, a neurobiologically-grounded theory of how behaviors like gambling can become addictive remains lacking, posing a significant hurdle for ongoing decisions in addiction nosology. This article integrates research on reward-related brain activity (functional MRI) and neurotransmitter function (PET) in GD, alongside the consideration of structural MRI data as to whether these signals more likely reflect pre-existing vulnerability or neuroadaptive change. Where possible, we point to qualitative similarities and differences with established markers for SUDs. Structural MRI studies indicate modest changes in regional gray matter volume and diffuse reductions in white matter integrity in GD, contrasting with clear structural deterioration in SUDs. Functional MRI studies consistently identify dysregulation in reward-related circuitry (primarily ventral striatum and medial prefrontal cortex), but evidence is mixed as to the direction of these effects. The need for further parsing of reward sub-processes is emphasized, including anticipation vs outcome, gains vs. losses, and disorder-relevant cues vs natural rewards. Neurotransmitter PET studies indicate amplified dopamine (DA) release in GD, in the context of minimal differences in baseline DA D2 receptor binding, highlighting a distinct profile from SUDs. Preliminary work has investigated further contributions of opioids, GABA and serotonin. Neuroimaging data increasingly highlight divergent profiles in GD vs. SUDs. The ability of gambling to perpetually activate DA (via maximal uncertainty) may contribute to neuroimaging similarities between GD and SUDs, whereas the supra-physiological DA effects of drugs may partly explain differences in the neuroimaging profile of the two syndromes. Coupled with consistent observations of correlations with gambling severity and related clinical variables within GD samples, the overall pattern of effects is interpreted as a likely combination of shared vulnerability markers across GD and SUDs, but with further experience-dependent neuroadaptive processes in GD.
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Affiliation(s)
- Luke Clark
- Centre for Gambling Research, University of British Columbia (UBC), Vancouver, BC, Canada.,Department of Psychology, University of British Columbia, Vancouver, BC, Canada
| | - Isabelle Boileau
- Addiction Imaging Research Group, Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada.,Vivian M. Rakoff PET Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Addictions Program, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Schizophrenia Program, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Martin Zack
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada. .,Clinical Neuroscience Program, Centre for Addiction and Mental Health, Toronto, ON, Canada. .,Department of Pharmacology & Toxicology, University of Toronto, Toronto, ON, Canada. .,Department of Public Health Sciences, University of Toronto, Toronto, ON, Canada.
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van Holst RJ, Sescousse G, Janssen LK, Janssen M, Berry AS, Jagust WJ, Cools R. Increased Striatal Dopamine Synthesis Capacity in Gambling Addiction. Biol Psychiatry 2018; 83:1036-1043. [PMID: 28728675 PMCID: PMC6698370 DOI: 10.1016/j.biopsych.2017.06.010] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 05/15/2017] [Accepted: 06/01/2017] [Indexed: 02/07/2023]
Abstract
BACKGROUND The hypothesis that dopamine plays an important role in the pathophysiology of pathological gambling is pervasive. However, there is little to no direct evidence for a categorical difference between pathological gamblers and healthy control subjects in terms of dopamine transmission in a drug-free state. Here we provide evidence for this hypothesis by comparing dopamine synthesis capacity in the dorsal and ventral parts of the striatum in 13 pathological gamblers and 15 healthy control subjects. METHODS This was achieved using [18F]fluoro-levo-dihydroxyphenylalanine dynamic positron emission tomography scans and striatal regions of interest that were hand-drawn based on visual inspection of individual structural magnetic resonance imaging scans. RESULTS Our results show that dopamine synthesis capacity was increased in pathological gamblers compared with healthy control subjects. Dopamine synthesis was 16% higher in the caudate body, 17% higher in the dorsal putamen, and 17% higher in the ventral striatum in pathological gamblers compared with control subjects. Moreover, dopamine synthesis capacity in the dorsal putamen and caudate head was positively correlated with gambling distortions in pathological gamblers. CONCLUSIONS Taken together, these results provide empirical evidence for increased striatal dopamine synthesis in pathological gambling.
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Amphetamine primes enhanced motivation toward uncertain choices in rats with genetic alcohol preference. Psychopharmacology (Berl) 2018; 235:1361-1370. [PMID: 29427080 DOI: 10.1007/s00213-018-4847-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 01/31/2018] [Indexed: 12/21/2022]
Abstract
RATIONALE Comorbidity with gambling disorder (GD) and alcohol use disorder (AUD) is well documented. OBJECTIVE The purpose of our study was to examine the influence of genetic alcohol drinking tendency on reward-guided decision making behavior of rats and the impact of dopamine releaser D-amphetamine on this behavior. METHODS In this study, Alko alcohol (AA) and Wistar rats went through long periods of operant lever pressing training where the task was to choose the profitable of two options. The lever choices were guided by different-sized sucrose rewards (one or three pellets), and the probability of gaining the larger reward was slowly changed to a level where choosing the smaller reward would be the most profitable in the long run. After training, rats were injected (s.c.) with dopamine releaser D-amphetamine (0.3, 1.0 mg/kg) to study the impact of rapid dopamine release on this learned decision making behavior. RESULTS Administration of D-amphetamine promoted unprofitable decision making of AA rats more robustly when compared to Wistar rats. At the same time, D-amphetamine reduced lever pressing responses. Interestingly, we found that this reduction in lever pressing was significantly greater in Wistar rats than in AA rats and it was not linked to motivation to consume sucrose. CONCLUSIONS Our results indicate that conditioning to the lever pressing in uncertain environments is more pronounced in AA than in Wistar rats and indicate that the reinforcing effects of a gambling-like environment act as a stronger conditioning factor for rats that exhibit a genetic tendency for high alcohol drinking.
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Zeeb FD, Li Z, Fisher DC, Zack MH, Fletcher PJ. Uncertainty exposure causes behavioural sensitization and increases risky decision-making in male rats: toward modelling gambling disorder. J Psychiatry Neurosci 2017; 42:404-413. [PMID: 28832319 PMCID: PMC5662462 DOI: 10.1503/jpn.170003] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND An animal model of gambling disorder, previously known as pathological gambling, could advance our understanding of the disorder and help with treatment development. We hypothesized that repeated exposure to uncertainty during gambling induces behavioural and dopamine (DA) sensitization - similar to chronic exposure to drugs of abuse. Uncertainty exposure (UE) may also increase risky decision-making in an animal model of gambling disorder. METHODS Male Sprague Dawley rats received 56 UE sessions, during which animals responded for saccharin according to an unpredictable, variable ratio schedule of reinforcement (VR group). Control animals responded on a predictable, fixed ratio schedule (FR group). Rats yoked to receive unpredictable reward were also included (Y group). Animals were then tested on the Rat Gambling Task (rGT), an analogue of the Iowa Gambling Task, to measure decision-making. RESULTS Compared with the FR group, the VR and Y groups experienced a greater locomotor response following administration of amphetamine. On the rGT, the FR and Y groups preferred the advantageous options over the risky, disadvantageous options throughout testing (40 sessions). However, rats in the VR group did not have a significant preference for the advantageous options during sessions 20-40. Amphetamine had a small, but significant, effect on decision-making only in the VR group. After rGT testing, only the VR group showed greater hyperactivity following administration of amphetamine compared with the FR group. LIMITATIONS Reward uncertainty was the only gambling feature modelled. CONCLUSION Actively responding for uncertain reward likely sensitized the DA system and impaired the ability to make optimal decisions, modelling some aspects of gambling disorder.
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Affiliation(s)
- Fiona D. Zeeb
- Correspondence to: F.D. Zeeb, Centre for Addiction and Mental Health (CAMH), 250 College St; Toronto ON M5T 1R8;
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The “highs and lows” of the human brain on dopaminergics: Evidence from neuropharmacology. Neurosci Biobehav Rev 2017. [DOI: 10.1016/j.neubiorev.2017.06.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Nautiyal KM, Okuda M, Hen R, Blanco C. Gambling disorder: an integrative review of animal and human studies. Ann N Y Acad Sci 2017; 1394:106-127. [PMID: 28486792 PMCID: PMC5466885 DOI: 10.1111/nyas.13356] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 03/08/2017] [Accepted: 03/22/2017] [Indexed: 11/29/2022]
Abstract
Gambling disorder (GD), previously called pathological gambling and classified as an impulse control disorder in DSM-III and DSM-IV, has recently been reclassified as an addictive disorder in the DSM-5. It is widely recognized as an important public health problem associated with substantial personal and social costs, high rates of psychiatric comorbidity, poor physical health, and elevated suicide rates. A number of risk factors have been identified, including some genetic polymorphisms. Animal models have been developed in order to study the underlying neural basis of GD. Here, we discuss recent advances in our understanding of the risk factors, disease course, and pathophysiology. A focus on a phenotype-based dissection of the disorder is included in which known neural correlates from animal and human studies are reviewed. Finally, current treatment approaches are discussed, as well as future directions for GD research.
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Affiliation(s)
- Katherine M. Nautiyal
- New York State Psychiatric Institute, New York, New York
- Department of Psychiatry, Columbia University, New York, New York
| | - Mayumi Okuda
- New York State Psychiatric Institute, New York, New York
- Department of Psychiatry, Columbia University, New York, New York
| | - Rene Hen
- New York State Psychiatric Institute, New York, New York
- Department of Psychiatry, Columbia University, New York, New York
- Departments of Neuroscience and Pharmacology, Columbia University, New York, New York
| | - Carlos Blanco
- National Institute on Drug Abuse, Rockville, Maryland
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Chen M, Sun Y, Lu L, Shi J. Similarities and Differences in Neurobiology. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1010:45-58. [PMID: 29098667 DOI: 10.1007/978-981-10-5562-1_3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Substance addiction is a chronic, relapsing brain disease characterized by compulsive drug seeking and use despite harmful consequences. Non-substance addiction is defined recently that people may compulsively engage in an activity despite any negative consequences to their lives. Despite differences with respect to their addictive object, substance addiction and non-substance addiction may share similarities with respect to biological, epidemiological, clinical, genetic and other features. Here we review the similarities and differences in neurobiology between these two addictions with a focus on dopamine, serotonin, opioid, glutamate and norepinephrine systems. Studies suggest the involvement of all these systems in both substance addiction and non-substance addiction while differences may exist with respect to their contributions.
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Affiliation(s)
- Manli Chen
- Department of Pharmacology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
- National Institute on Drug Dependence, Peking University, No. 38, Xueyuan Road, Haidian District, Beijing, 100191, China
| | - Yan Sun
- National Institute on Drug Dependence, Peking University, No. 38, Xueyuan Road, Haidian District, Beijing, 100191, China
| | - Lin Lu
- Institute of Mental Health/Peking University Sixth Hospital and National Clinical Research Center for Mental Disorders & Key Laboratory of Mental Health, Peking University, Beijing, 100191, China
| | - Jie Shi
- National Institute on Drug Dependence, Peking University, No. 38, Xueyuan Road, Haidian District, Beijing, 100191, China.
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16
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Zack MH, Lobo DS, Biback C, Fang T, Smart K, Tatone D, Kalia A, Digiacomo D, Kennedy JL. Parallel role for the dopamine D1 receptor in gambling and amphetamine reinforcement in healthy volunteers. J Psychopharmacol 2017; 31:31-42. [PMID: 27624149 DOI: 10.1177/0269881116665329] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
This study investigated the role of dopamine, and specifically the D1 receptor (D1R), in the reinforcing effects of a slot-machine game in healthy volunteers ( n=30). To compare gambling and drug effects, subjects received the prototypic psychostimulant drug d-amphetamine (AMPH; 20 mg) in a multi-session, placebo-controlled design. To isolate D1R, half the subjects were pretreated with the preferential D2 receptor antagonist haloperidol (HAL; 3 mg), and the other half with the mixed D1-D2 antagonist fluphenazine (FLU; 3 mg) before the game (Phase I) and AMPH (Phase II). HAL decreased and FLU increased the post-game desire to gamble and post-AMPH desire to take AMPH again, as well as amphetamine scale ratings on the Addiction Research Center Inventory after gambling and AMPH. The effects of the antagonists on desire to gamble and to take AMPH again were significantly intercorrelated. HAL increased and FLU decreased the salience of negative affective words on a rapid reading task after both reinforcers. HAL also decreased the salience of gambling words after AMPH. Both reinforcers increased diastolic blood pressure equally under antagonists and placebo. Results indicate that D1R plays a parallel role in the psychostimulant-like, incentive-motivational, and salience-enhancing effects of gambling and AMPH. Moderate D1R activation appears to optimize these effects in healthy subjects.
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Affiliation(s)
- Martin H Zack
- Centre for Addiction and Mental Health, Toronto, Canada
| | | | | | - Tim Fang
- Centre for Addiction and Mental Health, Toronto, Canada
| | - Kelly Smart
- Centre for Addiction and Mental Health, Toronto, Canada
| | - Daniel Tatone
- Centre for Addiction and Mental Health, Toronto, Canada
| | - Aditi Kalia
- Centre for Addiction and Mental Health, Toronto, Canada
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Medeiros GC, Leppink EW, Yaemi A, Mariani M, Tavares H, Grant JE. Electronic gaming machines and gambling disorder: A cross-cultural comparison between treatment-seeking subjects from Brazil and the United States. Psychiatry Res 2015; 230:430-5. [PMID: 26474662 PMCID: PMC4655154 DOI: 10.1016/j.psychres.2015.09.032] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 08/26/2015] [Accepted: 09/20/2015] [Indexed: 11/29/2022]
Abstract
AIMS The objective of this paper is to perform a cross-cultural comparison of gambling disorder (GD) due to electronic gaming machines (EGM), a form of gambling that may have a high addictive potential. Our goal is to investigate two treatment-seeking samples of adults collected in Brazil and the United States, countries with different socio-cultural backgrounds. This comparison may lead to a better understanding of cultural influences on GD. METHODS The total studied sample involved 733 treatment-seeking subjects: 353 men and 380 women (average age=45.80, standard deviation ±10.9). The Brazilian sample had 517 individuals and the American sample 216. Subjects were recruited by analogous strategies. RESULTS We found that the Brazilian sample was younger, predominantly male, less likely to be Caucasian, more likely to be partnered, tended to have a faster progression from recreational gambling to GD, and were more likely to endorse chasing losses. CONCLUSION This study demonstrated that there are significant differences between treatment-seeking samples of adults presenting GD due to EGM in Brazil and in the United States. These findings suggest that cultural aspects may have a relevant role in GD due to EGM.
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Affiliation(s)
- Gustavo Costa Medeiros
- Department of Psychiatry, University of São Paulo. São Paulo/SP, Brazil.,Corresponding author: Gustavo Costa Medeiros M.D; ; Adress: Rua Padre João Manuel, 173. Ap 71. São Paulo-SP; Zip Code: 01411-001; Phone: +55(11) 996471896; FAX: +55(11) 30639030
| | - Eric W. Leppink
- Department of Psychiatry, University of Chicago. Chicago/IL, United States
| | - Ana Yaemi
- Department of Psychiatry, University of São Paulo. São Paulo/SP, Brazil
| | - Mirella Mariani
- Department of Psychiatry, University of São Paulo. São Paulo/SP, Brazil
| | - Hermano Tavares
- Department of Psychiatry, University of São Paulo. São Paulo/SP, Brazil
| | - Jon E. Grant
- Department of Psychiatry, University of Chicago. Chicago/IL, United States
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Arrondo G, Aznárez-Sanado M, Fernández-Seara MA, Goñi J, Loayza FR, Salamon-Klobut E, Heukamp FH, Pastor MA. Dopaminergic modulation of the trade-off between probability and time in economic decision-making. Eur Neuropsychopharmacol 2015; 25:817-27. [PMID: 25840742 DOI: 10.1016/j.euroneuro.2015.02.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 10/16/2014] [Accepted: 02/25/2015] [Indexed: 11/28/2022]
Abstract
Studies on animals and humans have demonstrated the importance of dopamine in modulating decision-making processes. In this work, we have tested dopaminergic modulation of economic decision-making and its neural correlates by administering either placebo or metoclopramide, a dopamine D2-receptor antagonist, to healthy subjects, during a functional MRI study. The decision-making task combined probability and time delay with a fixed monetary reward. For individual behavioral characterization, we used the Probability Time Trade-off (PTT) economic model, which integrates the traditional trade-offs of reward magnitude-time and reward magnitude-probability into a single measurement, thereby quantifying the subjective value of a delayed and probabilistic outcome. A regression analysis between BOLD signal and the PTT model index permitted to identify the neural substrate encoding the subjective reward-value. Behaviorally, medication reduced the rate of temporal discounting over probability, reflected in medicated subjects being more prone to postpone the reward in order to increase the outcome probability. In addition, medicated subjects showed less activity during the task in the postcentral gyrus as well as frontomedian areas, whereas there were no differences in the ventromedial orbitofrontal cortex (VMOFC) between groups when coding the subjective value. The present study demonstrates by means of behavior and imaging that dopamine modulation alters the probability-time trade-off in human economic decision-making.
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Affiliation(s)
- Gonzalo Arrondo
- Functional Neuroimaging Laboratory, Division of Neurosciences, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain; Managerial Decision Sciences, IESE Business School, University of Navarra, 08034 Barcelona, Spain; Psychiatry Department, University of Cambridge, United Kingdom
| | - Maite Aznárez-Sanado
- Functional Neuroimaging Laboratory, Division of Neurosciences, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain
| | - Maria A Fernández-Seara
- Functional Neuroimaging Laboratory, Division of Neurosciences, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain
| | - Joaquín Goñi
- Functional Neuroimaging Laboratory, Division of Neurosciences, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain
| | - Francis R Loayza
- Functional Neuroimaging Laboratory, Division of Neurosciences, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain
| | - Ewa Salamon-Klobut
- Managerial Decision Sciences, IESE Business School, University of Navarra, 08034 Barcelona, Spain
| | - Franz H Heukamp
- Managerial Decision Sciences, IESE Business School, University of Navarra, 08034 Barcelona, Spain
| | - Maria A Pastor
- Functional Neuroimaging Laboratory, Division of Neurosciences, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain.
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Cocker P, Winstanley C. Irrational beliefs, biases and gambling: Exploring the role of animal models in elucidating vulnerabilities for the development of pathological gambling. Behav Brain Res 2015; 279:259-73. [DOI: 10.1016/j.bbr.2014.10.043] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 10/25/2014] [Accepted: 10/29/2014] [Indexed: 12/23/2022]
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Abnormal modulation of reward versus punishment learning by a dopamine D2-receptor antagonist in pathological gamblers. Psychopharmacology (Berl) 2015; 232:3345-53. [PMID: 26092311 PMCID: PMC4537492 DOI: 10.1007/s00213-015-3986-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 06/01/2015] [Indexed: 11/04/2022]
Abstract
RATIONALE Pathological gambling has been associated with dopamine transmission abnormalities, in particular dopamine D2-receptor deficiency, and reversal learning deficits. Moreover, pervasive theoretical accounts suggest a key role for dopamine in reversal learning. However, there is no empirical evidence for a direct link between dopamine, reversal learning and pathological gambling. OBJECTIVE The aim of the present study is to triangulate dopamine, reversal learning, and pathological gambling. METHODS Here, we assess the hypothesis that pathological gambling is accompanied by dopamine-related problems with learning from reward and punishment by investigating effects of the dopamine D2-receptor antagonist sulpiride (400 mg) on reward- and punishment-based reversal learning in 18 pathological gamblers and 22 healthy controls, using a placebo-controlled, double-blind, counter-balanced design. RESULTS In line with previous studies, blockade of D2 receptors with sulpiride impaired reward versus punishment reversal learning in controls. By contrast, sulpiride did not have any outcome-specific effects in gamblers. CONCLUSION These data demonstrate that pathological gambling is associated with a dopamine-related anomaly in reversal learning from reward and punishment.
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21
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D'Amour-Horvat V, Leyton M. Impulsive actions and choices in laboratory animals and humans: effects of high vs. low dopamine states produced by systemic treatments given to neurologically intact subjects. Front Behav Neurosci 2014; 8:432. [PMID: 25566001 PMCID: PMC4274964 DOI: 10.3389/fnbeh.2014.00432] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 11/26/2014] [Indexed: 11/13/2022] Open
Abstract
Increases and decreases in dopamine (DA) transmission have both been suggested to influence reward-related impulse-control. The present literature review suggests that, in laboratory animals, the systemic administration of DA augmenters preferentially increases susceptibility to premature responding; with continued DA transmission, reward approach behaviors are sustained. Decreases in DA transmission, in comparison, diminish the appeal of distal and difficult to obtain rewards, thereby increasing susceptibility to temporal discounting and other forms of impulsive choice. The evidence available in humans is not incompatible with this model but is less extensive.
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Affiliation(s)
| | - Marco Leyton
- Department of Psychology, McGill University Montreal, QC, Canada ; Department of Psychiatry, McGill University Montreal, QC, Canada ; Center for Studies in Behavioral Neurobiology, Concordia University Montreal, QC, Canada
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22
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Haloperidol blocks dorsal striatum activity but not analgesia in a placebo paradigm. Cortex 2014; 57:60-73. [DOI: 10.1016/j.cortex.2014.02.023] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 10/08/2013] [Accepted: 02/27/2014] [Indexed: 12/19/2022]
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Zack M, Featherstone RE, Mathewson S, Fletcher PJ. Chronic exposure to a gambling-like schedule of reward predictive stimuli can promote sensitization to amphetamine in rats. Front Behav Neurosci 2014; 8:36. [PMID: 24574987 PMCID: PMC3920462 DOI: 10.3389/fnbeh.2014.00036] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 01/23/2014] [Indexed: 12/22/2022] Open
Abstract
Addiction is considered to be a brain disease caused by chronic exposure to drugs. Sensitization of brain dopamine (DA) systems partly mediates this effect. Pathological gambling (PG) is considered to be a behavioral addiction. Therefore, PG may be caused by chronic exposure to gambling. Identifying a gambling-induced sensitization of DA systems would support this possibility. Gambling rewards evoke DA release. One episode of slot machine play shifts the DA response from reward delivery to onset of cues (spinning reels) for reward, in line with temporal difference learning principles. Thus, conditioned stimuli (CS) play a key role in DA responses to gambling. In primates, DA response to a CS is strongest when reward probability is 50%. Under this schedule the CS elicits an expectancy of reward but provides no information about whether it will occur on a given trial. During gambling, a 50% schedule should elicit maximal DA release. This closely matches reward frequency (46%) on a commercial slot machine. DA release can contribute to sensitization, especially for amphetamine. Chronic exposure to a CS that predicts reward 50% of the time could mimic this effect. We tested this hypothesis in three studies with rats. Animals received 15 × 45-min exposures to a CS that predicted reward with a probability of 0, 25, 50, 75, or 100%. The CS was a light; the reward was a 10% sucrose solution. After training, rats received a sensitizing regimen of five separate doses (1 mg/kg) of d-amphetamine. Lastly they received a 0.5 or 1 mg/kg amphetamine challenge prior to a 90-min locomotor activity test. In all three studies the 50% group displayed greater activity than the other groups in response to both challenge doses. Effect sizes were modest but consistent, as reflected by a significant group × rank association (ϕ = 0.986, p = 0.025). Chronic exposure to a gambling-like schedule of reward predictive stimuli can promote sensitization to amphetamine much like exposure to amphetamine itself.
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Affiliation(s)
- Martin Zack
- Cognitive Psychopharmacology Laboratory, Neuroscience Department, Centre for Addiction and Mental Health Toronto, ON, Canada
| | - Robert E Featherstone
- Translational Neuroscience Program, Department of Psychiatry, School of Medicine, University of Pennsylvania Philadelphia, PA, USA
| | - Sarah Mathewson
- Biopsychology Section, Neuroscience Department, Centre for Addiction and Mental Health Toronto, ON, Canada
| | - Paul J Fletcher
- Biopsychology Section, Neuroscience Department, Centre for Addiction and Mental Health Toronto, ON, Canada
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Angelucci F, Martinotti G, Gelfo F, Righino E, Conte G, Caltagirone C, Bria P, Ricci V. Enhanced BDNF serum levels in patients with severe pathological gambling. Addict Biol 2013; 18:749-51. [PMID: 22044515 DOI: 10.1111/j.1369-1600.2011.00411.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although the pathophysiology of gambling is unknown, an involvement of midbrain dopaminergic pathway has been hypothesized. In this study, the association between brain-derived neurotrophic factor (BDNF) and pathological gambling was investigated. We measured BDNF serum levels in (1) video players (n=10); (2) card players (n=9); (3) mixed players (n=21; both video and card players) and (4) age-matched controls (n=18). Mixed players had increased BDNF serum levels as compared to controls and higher South Oaks Gambling Screen score as compared to card or video players. Thus, the data demonstrate that patients affected by severe pathological gambling show enhanced BDNF serum levels.
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Affiliation(s)
- Francesco Angelucci
- IRCCS Santa Lucia Foundation, Department of Clinical and Behavioural Neurology, Rome, Italy Institute of Psychiatry, Catholic University, Rome, Italy.
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Smart K, Desmond RC, Poulos CX, Zack M. Modafinil increases reward salience in a slot machine game in low and high impulsivity pathological gamblers. Neuropharmacology 2013; 73:66-74. [PMID: 23711549 DOI: 10.1016/j.neuropharm.2013.05.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 05/06/2013] [Accepted: 05/09/2013] [Indexed: 10/26/2022]
Abstract
This study examined the effects of modafinil (200 mg) on slot machine betting profiles from a previous sample of low and high impulsivity (LI/HI) pathological gamblers (10/Group; Zack and Poulos, 2009). Hierarchical regression assessed the prospective relationship between Payoff and Bet Size on consecutive trials, along with moderating effects of Group, Cumulative Winnings (low/high) and Phase of game (early/late) under drug and placebo. Y intercepts for the simple regressions of Bet Size on Payoff indexed overall motivation to bet. Under placebo, both groups gauged their bets less closely to the preceding Payoff as trials continued when Winnings were low but not high. Under modafinil, both groups gauged their bets more closely to the preceding Payoff when Winnings were low but gauged their bets less closely to the previous Payoff when Winnings were high. The tendency to gauge bets closely to the previous Payoff coincided with a bias toward low overall Bet Size, and modafinil accentuated this relationship, in LI but not HI subjects. Results suggest that modafinil increases the salience of environmental rewards, leading to more tightly calibrated responses to individual rewards when resources are low, but progressively loosens reward-response calibration when resources are high. Increased relative impact of phasic vs. tonic dopamine signals may account for patterns seen at low vs. high Winnings, respectively, under the drug. Clinically, modafinil may deter pathological gamblers from chasing losses but also encourage them to continue betting rather than quit while they are ahead. Whether low-dose modafinil confers more uniform benefits deserves investigation.
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Affiliation(s)
- Kelly Smart
- Centre for Addiction and Mental Health, 33 Russell Street, Toronto, Ontario M5S 2S1, Canada
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26
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Leeman RF, Potenza MN. A targeted review of the neurobiology and genetics of behavioural addictions: an emerging area of research. CANADIAN JOURNAL OF PSYCHIATRY. REVUE CANADIENNE DE PSYCHIATRIE 2013; 58:260-73. [PMID: 23756286 PMCID: PMC3762982 DOI: 10.1177/070674371305800503] [Citation(s) in RCA: 158] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
This review summarizes neurobiological and genetic findings in behavioural addictions, draws parallels with findings pertaining to substance use disorders, and offers suggestions for future research. Articles concerning brain function, neurotransmitter activity, and family history and (or) genetic findings for behavioural addictions involving gambling, Internet use, video game playing, shopping, kleptomania, and sexual activity were reviewed. Behavioural addictions involve dysfunction in several brain regions, particularly the frontal cortex and striatum. Findings from imaging studies incorporating cognitive tasks have arguably been more consistent than cue-induction studies. Early results suggest white and grey matter differences. Neurochemical findings suggest roles for dopaminergic and serotonergic systems, but results from clinical trials seem more equivocal. While limited, family history and genetic data support heritability for pathological gambling and that people with behavioural addictions are more likely to have a close family member with some form of psychopathology. Parallels exist between neurobiological and genetic and family history findings in substance and nonsubstance addictions, suggesting that compulsive engagement in these behaviours may constitute addictions. To date, findings are limited, particularly for shopping, kleptomania, and sexual behaviour. Genetic understandings are at an early stage. Future research directions are offered.
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MESH Headings
- Behavior, Addictive/classification
- Behavior, Addictive/genetics
- Behavior, Addictive/metabolism
- Behavior, Addictive/physiopathology
- Behavioral Research/methods
- Brain/metabolism
- Brain/physiopathology
- Disruptive, Impulse Control, and Conduct Disorders/classification
- Disruptive, Impulse Control, and Conduct Disorders/diagnosis
- Disruptive, Impulse Control, and Conduct Disorders/genetics
- Disruptive, Impulse Control, and Conduct Disorders/metabolism
- Disruptive, Impulse Control, and Conduct Disorders/psychology
- Functional Neuroimaging/methods
- Genetic Predisposition to Disease
- Genetics, Behavioral/methods
- Humans
- Neurobiology/methods
- Neuropsychology/methods
- Neurotransmitter Agents/classification
- Neurotransmitter Agents/metabolism
- Substance-Related Disorders/metabolism
- Substance-Related Disorders/physiopathology
- Substance-Related Disorders/psychology
- Synaptic Transmission/physiology
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Affiliation(s)
- Robert F Leeman
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA.
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Systemic administration of 8-OH-DPAT and eticlopride, but not SCH23390, alters loss-chasing behavior in the rat. Neuropsychopharmacology 2013; 38:1094-104. [PMID: 23303072 PMCID: PMC3629409 DOI: 10.1038/npp.2013.8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Gambling to recover losses is a common gaming behavior. In a clinical context, however, this phenomenon mediates the relationship between diminished control over gambling and the adverse socioeconomic consequences of gambling problems. Modeling loss-chasing through analogous behaviors in rats could facilitate its pharmacological investigation as a potential therapeutic target. Here, rats were trained to make operant responses that produced both food rewards, and unpredictably, imminent time-out periods in which rewards would be unavailable. At these decision points, rats were offered choices between waiting for these time-out periods to elapse before resuming responding for rewards ('quit' responses), or selecting risky options with a 0.5 probability of avoiding the time-outs altogether and a 0.5 probability of time-out periods twice as long as signaled originally ('chase' responses). Chasing behavior, and the latencies to chase or quit, during sequences of unfavorable outcomes were tested following systemic administration of the 5-HT1A receptor agonist, 8-OH-DPAT, the D2 receptor antagonist, eticlopride, and the D1 receptor antagonist, SCH23390. 8-OH-DPAT and eticlopride significantly reduced the proportion of chase responses, and the mean number of consecutive chase responses, in a dose-dependent manner. 8-OH-DPAT also increased latencies to chase. Increasing doses of eticlopride first speeded, then slowed, latencies to quit while SCH23390 had no significant effects on any measure. Research is needed to identify the precise cognitive mechanisms mediating these kinds of risky choices in rats. However, our data provide the first experimental demonstration that 5-HT1A and D2, but not D1, receptor activity influence a behavioral analog of loss-chasing in rats.
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Boileau I, Payer D, Chugani B, Lobo D, Behzadi A, Rusjan PM, Houle S, Wilson AA, Warsh J, Kish SJ, Zack M. The D2/3 dopamine receptor in pathological gambling: a positron emission tomography study with [11C]-(+)-propyl-hexahydro-naphtho-oxazin and [11C]raclopride. Addiction 2013; 108:953-63. [PMID: 23167711 DOI: 10.1111/add.12066] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 07/05/2012] [Accepted: 11/09/2012] [Indexed: 11/27/2022]
Abstract
AIMS Pathological gambling (PG) shares diagnostic features with substance use disorder (SUD), but the neurochemical mechanisms underlying PG are poorly understood. Because dopamine (DA), a neurotransmitter implicated in reward and reinforcement, is probably involved, we used positron emission tomography (PET) to test whether PG is associated with abnormalities in D2 and D3 receptor levels, as observed in SUD. DESIGN Case-control study comparing PG to healthy control (HC) subjects. SETTING Academic research imaging centre. PARTICIPANTS Thirteen non-treatment-seeking males meeting DSM-IV criteria for PG, and 12 matched HC (11 of whom completed PET). MEASUREMENTS Two PET scans (one with the D3 receptor preferring agonist [11C]-(+)-propyl-hexahydro-naphtho-oxazin (PHNO) and the other with [11C]raclopride) to assess D(2/3) DA receptor availability, and behavioural measures (self-report questionnaires and slot-machine game) to assess subjective effects and relationships to PET measures. FINDINGS Binding of both radiotracers did not differ between groups in striatum or substantia nigra (SN) (all P > 0.1). Across PG, [11C]-(+)-PHNO binding in SN, where the signal is attributable primarily to D3 receptors, correlated with gambling severity (r = 0.57, P = 0.04) and impulsiveness (r = 0.65, P = 0.03). In HC, [11C]raclopride binding in dorsal striatum correlated inversely with subjective effects of gambling (r = -0.70, P = 0.03) and impulsiveness (r = -0.70, P = 0.03). CONCLUSIONS Unlike with substance use disorder, there appear to be no marked differences in D2 /D3 levels between healthy subjects and pathological gamblers, suggesting that low receptor availability may not be a necessary feature of addiction. However, relationships between [11C]-(+)-PHNO binding and gambling severity/impulsiveness suggests involvement of the D3 receptor in impulsive/compulsive behaviours.
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Affiliation(s)
- Isabelle Boileau
- Addiction Imaging Research Group, Centre for Addiction and Mental Health, Toronto, ON, Canada.
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Shao R, Read J, Behrens TEJ, Rogers RD. Shifts in reinforcement signalling while playing slot-machines as a function of prior experience and impulsivity. Transl Psychiatry 2013; 3:e213. [PMID: 23321810 PMCID: PMC3566715 DOI: 10.1038/tp.2012.134] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Electronic gaming machines (EGMs) offer significant revenue streams for mercantile gambling. However, limited clinical and experimental evidence suggests that EGMs are associated with heightened risks of clinically problematic patterns of play. Little is known about the neural structures that might mediate the transition from exploratory EGM play to the 'addictive' play seen in problem gamblers; neither is it known how personality traits associated with gambling activity (and gambling problems) influence reinforcement processing while playing EGMs. Using functional magnetic resonance imaging in healthy participants, we show that a single episode of slot-machine play is subsequently associated with reduced amplitudes of blood-oxygenation-level-dependent signals within reinforcement-related structures, such as the ventral striatum and caudate nucleus, following winning game outcomes; but increased amplitudes of anticipatory signals within the ventral striatum and amygdala while watching the game reels spin. Trait impulsivity enhanced positive signals within the ventral striatum and amygdala following the delivery of winning outcomes but diminished positive signals following the experience of almost-winning ('near-misses'). These results indicate that a single episode of slot-machine play engages the well-characterised reinforcement-learning mechanisms mediated by ascending dopamine mesolimbic and mesostriatal pathways, to shift reward value of EGMs away from game outcomes towards anticipatory states. Impulsivity, itself linked to problem gambling and heightened vulnerability to other addictive disorders, is associated with divergent coding of winning outcomes and almost-winning experiences within the ventral striatum and amygdala, potentially enhancing the reward value of successful slot-machine game outcomes but, at the same time, modulating the aversive motivational consequences of near-miss outcomes.
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Affiliation(s)
- R Shao
- Department of Psychiatry, University of Oxford, Oxford, UK
| | - J Read
- Department of Psychiatry, University of Oxford, Oxford, UK
| | - T E J Behrens
- Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford, Oxford, UK
| | - R D Rogers
- Department of Psychiatry, University of Oxford, Oxford, UK,University Department of Psychiatry, Warneford Hospital, Oxford OX3 7JX, UK. E-mail:
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Leeman RF, Potenza MN. Similarities and differences between pathological gambling and substance use disorders: a focus on impulsivity and compulsivity. Psychopharmacology (Berl) 2012; 219:469-90. [PMID: 22057662 PMCID: PMC3249521 DOI: 10.1007/s00213-011-2550-7] [Citation(s) in RCA: 259] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 10/13/2011] [Indexed: 12/11/2022]
Abstract
RATIONALE Pathological gambling (PG) has recently been considered as a "behavioral" or nonsubstance addiction. A comparison of the characteristics of PG and substance use disorders (SUDs) has clinical ramifications and could help advance future research on these conditions. Specific relationships with impulsivity and compulsivity may be central to understanding PG and SUDs. OBJECTIVES This review was conducted to compare and contrast research findings in PG and SUDs pertaining to neurocognitive tasks, brain function, and neurochemistry, with a focus on impulsivity and compulsivity. RESULTS Multiple similarities were found between PG and SUDs, including poor performance on neurocognitive tasks, specifically with respect to impulsive choice and response tendencies and compulsive features (e.g., response perseveration and action with diminished relationship to goals or reward). Findings suggest dysfunction involving similar brain regions, including the ventromedial prefrontal cortex and striatum and similar neurotransmitter systems, including dopaminergic and serotonergic. Unique features exist which may in part reflect influences of acute or chronic exposures to specific substances. CONCLUSIONS Both similarities and differences exist between PG and SUDs. Understanding these similarities more precisely may facilitate treatment development across addictions, whereas understanding differences may provide insight into treatment development for specific disorders. Individual differences in features of impulsivity and compulsivity may represent important endophenotypic targets for prevention and treatment strategies.
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Affiliation(s)
- Robert F Leeman
- Department of Psychiatry, Yale University School of Medicine, CMHC, 34 Park Street, New Haven, CT 06405, USA.
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Dopamine modulates reward expectancy during performance of a slot machine task in rats: evidence for a 'near-miss' effect. Neuropsychopharmacology 2011; 36:913-25. [PMID: 21209612 PMCID: PMC3077261 DOI: 10.1038/npp.2010.230] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Cognitive accounts of gambling suggest that the experience of almost winning-so-called 'near-misses'-encourage continued play and accelerate the development of pathological gambling (PG) in vulnerable individuals. One explanation for this effect is that near-misses signal imminent winning outcomes and heighten reward expectancy, galvanizing further play. Determining the neurochemical processes underlying the drive to gamble could facilitate the development of more effective treatments for PG. With this aim in mind, we evaluated rats' performance on a novel model of slot machine play, a form of gambling in which near-miss events are particularly salient. Subjects responded to a series of three flashing lights, loosely analogous to the wheels of a slot machine, causing the lights to set to 'on' or 'off'. A winning outcome was signaled if all three lights were illuminated. At the end of each trial, rats chose between responding on the 'collect' lever, resulting in reward on win trials, but a time penalty on loss trials, or starting a new trial. Rats showed a marked preference for the collect lever when both two and three lights were illuminated, indicating heightened reward expectancy following near-misses similar to wins. Erroneous collect responses were increased by amphetamine and the D(2) receptor agonist quinpirole, but not by the D(1) receptor agonist SKF 81297 or receptor subtype selective antagonists. These data suggest that dopamine modulates reward expectancy following the experience of almost winning during slot machine play, via activity at D(2) receptors, and this may result in an enhancement of the near-miss effect and facilitate further gambling.
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