Cross-species approaches to pathological gambling: a review targeting sex differences, adolescent vulnerability and ecological validity of research tools

Regulation of sex differences in risk-based decision making by gonadal hormones: Insights from rodent models

Men and women differ in their ability to evaluate options that vary in their rewards and the risks that are associated with these outcomes. Most studies have shown that women are more risk averse than men and that gonadal hormones significantly contribute to this sex difference. Gonadal hormones can influence risk-based decision making (i.e., risk taking) by modulating the neurobiological substrates underlying this cognitive process. Indeed, estradiol, progesterone and testosterone modulate activity in the prefrontal cortex, amygdala and nucleus accumbens associated with reward and risk-related information. The use of animal models of decision making has advanced our understanding of the intersection between the behavioral, neural and hormonal mechanisms underlying sex differences in risk taking. This review will outline the current state of this literature, identify the current gaps in knowledge and suggest the neurobiological mechanisms by which hormones regulate risky decision making. Collectively, this knowledge can be used to understand the potential consequences of significant hormonal changes, whether endogenously or exogenously induced, on risk-based decision making as well as the neuroendocrinological basis of neuropsychiatric diseases that are characterized by impaired risk taking, such as substance use disorder and schizophrenia.

Behavior of Rats in a Self-Paced Risky Decision-Making Task Based on Definite Probability

Risky decision-making (RDM) is when individuals make choices based on the definite cognition for the probabilities of the options. Risk is embodied in the certainty of reward, and the smaller the probability is, the greater the risk will be. As simulated in human behavior paradigms, RDM scenarios in real life are often guided by external cues that inform the likelihood of receiving certain rewards. There are few studies on the neural basis of RDM behavior guided by external cues, which is related to the relative paucity of the animal behavioral paradigms. Here, we established a cue-guided RDM task to detect the behavior of rats making a decision between a small certain reward and a large uncertain reward in a naturalistic manner. The reward of the risk option could be adjusted to observe the change of choice. Our results showed that: (1) rats were able to master the operation of the cue-guided RDM task; (2) many rats were inclined to choose risk rather than the safe option when the reward expectations were equal; (3) rats were able to adjust the decision strategy in time upon a change in risk, suggesting that they have the ability to perceive risk indicated by the external cues.

Inter-Individual Differences in Cognitive Tasks: Focusing on the Shaping of Decision-Making Strategies

In this paper, we review recent (published and novel) data showing inter-individual variation in decision-making strategies established by mice in a gambling task (MGT for Mouse Gambling Task). It may look intriguing, at first, that congenic animals develop divergent behaviors. However, using large groups of mice, we show that individualities emerge in the MGT, with about 30% of healthy mice displaying risk-averse choices while about 20-25% of mice make risk-prone choices. These strategies are accompanied by different brain network mobilization and individual levels of regional -prefrontal and striatal- monoamines. We further illustrate three ecological ways that influence drastically cognitive strategies in healthy adult mice: sleep deprivation, sucrose or artificial sweetener exposure, and regular exposure to stimulating environments. Questioning how to unmask individual strategies, what are their neural/neurochemical bases and whether we can shape or reshape them with different environmental manipulations is of great value, first to understand how the brain may build flexible decisions, and second to study behavioral plasticity, in healthy adult, as well as in developing brains. The latter may open new avenues for the identification of vulnerability traits to adverse events, before the emergence of mental pathologies.

Functional connectivity in reward-related networks is associated with individual differences in gambling strategies in male Lister hooded rats

Individuals with gambling disorder display deficits in decision-making in the Iowa Gambling Task. The rat Gambling Task (rGT) is a rodent analogue that can be used to investigate the neurobiological mechanisms underlying gambling behaviour. The aim of this explorative study was to examine individual strategies in the rGT and investigate possible behavioural and neural correlates associated with gambling strategies. Thirty-two adult male Lister hooded rats underwent behavioural testing in the multivariate concentric square field™ (MCSF) and the novel cage tests, were trained on and performed the rGT and subsequently underwent resting-state functional magnetic resonance imaging (R-fMRI). In the rGT, stable gambling strategies were found with subgroups of rats that preferred the suboptimal safest choice as well as the disadvantageous choice, that is, the riskiest gambling strategy. R-fMRI results revealed associations between gambling strategies and brain regions central for reward networks. Moreover, rats with risky gambling strategies differed from those with strategic and intermediate strategies in brain functional connectivity. No differences in behavioural profiles, as assessed with the MCSF and novel cage tests, were observed between the gambling strategy groups. In conclusion, stable individual differences in gambling strategies were found. Intrinsic functional connectivity using R-fMRI provides novel evidence to support the notion that individual differences in gambling strategies are associated with functional connectivity in brain regions important for reward networks.

Pharmacological and Psychosocial Treatment of Adults With Gambling Disorder: A Meta-Review

BACKGROUND AND OBJECTIVES

Gambling disorder (GD) leads to impaired socioeconomical functioning and increased social costs. Although the research on GD has been rising over the years, approved treatment guidelines are currently not available. The aim of this study was to systematically review the literature on the pharmacological and psychosocial treatment of adults with GD, and to identify possible agreed-upon standards of care.

METHODS

MEDLINE, PubMed, Cochrane, Web of Science, Embase, and CINAHL electronic databases were searched up to April 2019 for systematic reviews on pharmacological, psychosocial, and combined treatment of adults with GD. Twenty-six studies were eventually included in this meta-review.

RESULTS

Studies reported promising results of opioid antagonists and mood stabilizers in reducing GD-related symptomatology. Lithium was particularly effective in subjects with comorbid bipolar disorders. Cognitive behavioral therapy (CBT) was the most commonly used psychological intervention and reduced global severity, gambling frequency, and financial loss. Motivational interviewing (MI) seemed to improve several GD domains, alone or in combination with CBT. Self-help interventions (SHIs) showed some efficacy in promoting treatment-seeking, and in combination with other treatments.

CONCLUSIONS

We found moderate evidence of effect for CBT, but weaker evidence for pharmacotherapy and SHIs. Results suggested some efficacy for MI in the short but not in the long term. It is likely that certain interventions might be more effective than others on specific features of GD. Further studies are needed to compare the efficacy and acceptability of individual and combined psychosocial and pharmacological interventions, to deliver patient-tailored treatments.

Gambling-related harms attributable to lotteries products

Lotteries products (lottery tickets and scratch tickets) are the most popular forms of gambling worldwide, however little research has investigated whether these products are associated with gambling-related harm. The limited available research suggests these products are linked to problematic gambling behaviors and a range of resulting negative outcomes, with certain sub-groups appearing to be more vulnerable to experiencing harms. The present study examined risk of gambling-related harm (measured by the Problem Gambling Severity Index) from lotteries products use in an Australian sample of lotteries-only gamblers (n = 540). Additionally, the study investigated whether risk varied according to a range of sociodemographic and behavioral characteristics (age, gender, household income, location (rural vs. metropolitan), employment status, alcohol consumption, smoking status, frequency of e-cigarette use, frequency of scratch ticket use, frequency of lottery ticket use, expenditure on scratch tickets, and expenditure on lottery tickets). Almost one-third of the sample was found to be at some level of gambling-related risk due to their use of lotteries products. Younger respondents, males, current smokers, e-cigarette users, and those who purchase scratch tickets more frequently were more likely to report problematic use of lotteries products. Policy makers should enact strategies to prevent and reduce harms resulting from lotteries products, especially among the identified at-risk groups.

Modelling decision-making under uncertainty: A direct comparison study between human and mouse gambling data

Decision-making is a conserved evolutionary process enabling us to choose one option among several alternatives, and relies on reward and cognitive control systems. The Iowa Gambling Task allows the assessment of human decision-making under uncertainty by presenting four card decks with various cost-benefit probabilities. Participants seek to maximise their monetary gain by developing long-term optimal-choice strategies. Animal versions have been adapted with nutritional rewards, but interspecies data comparisons are scarce. Our study directly compares the non-pathological decision-making performance between humans and wild-type C57BL/6 mice. Human participants completed an electronic Iowa Gambling Task version, while mice a maze-based adaptation with four arms baited in a probabilistic way. Our data shows closely matching performance between both species with similar patterns of choice behaviours. However, mice showed a faster learning rate than humans. Moreover, both populations were clustered into good, intermediate and poor decision-making categories with similar proportions. Remarkably, mice characterised as good decision-makers behaved the same as humans of the same category, but slight differences among species are evident for the other two subpopulations. Overall, our direct comparative study confirms the good face validity of the rodent gambling task. Extended behavioural characterisation and pathological animal models should help strengthen its construct validity and disentangle the determinants in animals and humans decision-making.

Inter-individual and inter-strain differences in cognitive and social abilities of Dark Agouti and Wistar Han rats

Healthy animals displaying extreme behaviours that resemble human psychiatric symptoms are relevant models to study the natural psychobiological processes of maladapted behaviours. Using a Rat Gambling Task, healthy individuals spontaneously making poor decisions (PDMs) were found to co-express a combination of other cognitive and reward-based characteristics similar to symptoms observed in human patients with impulse-control disorders. The main goals of this study were to 1) confirm the existence of PDMs and their unique behavioural phenotypes in Dark Agouti (DA) and Wistar Han (WH) rats, 2) to extend the behavioural profile of the PDMs to probability-based decision-making and social behaviours and 3) to extract key discriminative traits between DA and WH strains, relevant for biomedical research. We have compared cognitive abilities, natural behaviours and physiological responses in DA and WH rats at the strain and at the individual level. Here we found that the naturally occurring PDM's profile was consistent between both rat lines. Then, although the PDM individuals did not take more risks in probability discounting task, they seemed to be of higher social ranks. Finally and despite their similarities in performance, WH and DA lines differed in degree of reward sensitivity, impulsivity, locomotor activity and open space-occupation. The reproducibility and conservation of the complex phenotypes of PDMs and GDMs (good decision makers) in these two genetically different strains support their translational potential. Both strains, present large phenotypic variation in behaviours pertinent for the study of the underlying mechanisms of poor decision making and associated disorders.

Sexually dimorphic behavioral and neural responses to a predator scent

Male and female C57BL/6 J mice were tested on the predator odor response task, where they needed to cross through a chamber of scented bedding to reach a sucrose reward. Following the behavioral testing, mouse brains were immunohistochemically labeled for expression of the immediate early gene c-fos. In the presence of the novel odorant methyl valerate (MV), both males and females exhibited increased exploration behaviors and delayed rewards compared to control bedding. However, in the presence of the predator odor phenylethylamine (PEA), males exhibited increased exploration that strongly resembled their behavior in MV (a non-predator odor) while females behaved very similarly to the clean bedding controls, quickly traversing the chamber to achieve the reward. Expression of c-fos exhibited significant sex by odor condition interactions overall across brain regions and in the anterior piriform cortex, cingulate cortex, and dorsomedial hypothalamus specifically. In all three regions we observed the general pattern that PEA exposure evoked elevated c-fos expression in females but suppressed c-fos expression in males. Taken together these data suggest that males and females may adopt different behavioral strategies in the presence of predator threat.

Effects of 5-HT2C, 5-HT1A receptor challenges and modafinil on the initiation and persistence of gambling behaviours

RATIONALE

Problematic patterns of gambling are characterised by loss of control and persistent gambling often to recover losses. However, little is known about the mechanisms that mediate initial choices to begin gambling and then continue to gamble in the face of losing outcomes.

OBJECTIVES

These experiments first assessed gambling and loss-chasing performance under different win/lose probabilities in C57Bl/6 mice, and then investigated the effects of antagonism of 5-HT_2CR with SB242084, 5-HT_1AR agonism with 8-OH-DPAT and modafinil, a putative cognitive enhancer.

RESULTS

As seen in humans and other species, mice demonstrated the expected patterns of behaviour as the odds for winning were altered increasing gambling and loss-chasing when winning was more likely. SB242084 decreased the likelihood to initially gamble, but had no effects on subsequent gambling choices in the face of repeated losses. In contrast, 8-OH-DPAT had no effects on choosing to gamble in the first place, but once started 8-OH-DPAT increased gambling choices in a dose-sensitive manner. Modafinil effects were different to the serotonergic drugs in both decreasing the propensity to initiate gambling and chase losses.

CONCLUSIONS

We present evidence for dissociable effects of systemic drug administration on different aspects of gambling behaviour. These data extend and reinforce the importance of serotonergic mechanisms in mediating discrete components of gambling behaviour. They further demonstrate the ability of modafinil to reduce gambling behaviour. Our work using a novel mouse paradigm may be of utility in modelling the complex psychological and neurobiological underpinnings of gambling problems, including the analysis of genetic and environmental factors.

Review: brain neurobiology of gambling disorder based on rodent models

Different literature reviews of gambling disorder (GD) neurobiology have been focused on human studies, others have focused on rodents, and others combined human and rodent studies. The main question of this review was: which are the main neurotransmitters systems and brain structures relevant for GD based on recent rodent studies? This work aims to review the experimental findings regarding the rodent´s neurobiology of GD. A search in the Pub Med database was set (October 2012-October 2017) and 162 references were obtained. After screening, 121 references were excluded, and only 41 references remained from the initial output. More, other 25 references were added to complement (introduction section, neuroanatomical descriptions) the principal part of the work. At the end, a total of 66 references remained for the review. The main conclusions are: 1) according to studies that used noninvasive methods for drug administration, some of the neurotransmitters and receptors involved in behaviors related to GD are: muscarinic, N-methyl-D-aspartate (NMDA), cannabinoid receptor 1 (CB₁), cannabinoid receptor 2 (CB₂), dopamine 2 receptor (D₂), dopamine 3 receptor (D₃), and dopamine 4 receptor (D₄); 2) moreover, there are other neurotransmitters and receptors involved in GD based on studies that use invasive methods of drug administration (eg, brain microinjection); example of these are: serotonin 1A receptor (5-HT_1A), noradrenaline receptors, gamma-aminobutyric acid receptor A (GABA_A), and gamma-aminobutyric acid receptor B (GABA_B); 3) different brain structures are relevant to behaviors linked to GD, like: amygdala (including basolateral amygdala (BLA)), anterior cingulate cortex (ACC), hippocampus, infralimbic area, insular cortex (anterior and rostral agranular), nucleus accumbens (NAc), olfactory tubercle (island of Calleja), orbitofrontal cortex (OFC), medial prefrontal cortex (mPFC), prefrontal cortex (PFC) - subcortical network, striatum (ventral) and the subthalamic nucleus (STN); and 4) the search for GD treatments should consider this diversity of receptor/neurotransmitter systems and brain areas.

Let's call the whole thing off: evaluating gender and sex differences in executive function

The executive functions allow for purposeful, deliberate, and intentional interactions with the world-attention and focus, impulse control, decision making, and working memory. These measures have been correlated with academic outcomes and quality of life, and are impacted by deleterious environmental events throughout the life span, including gestational and early life insults. This review will address the topic of sex differences in executive function including a discussion of differences arising in response to developmental programming. Work on gender differences in human studies and sex differences in animal research will be reviewed. Overall, we find little support for significant gender or sex differences in executive function. An important variable that factors into the interpretation of potential sex differences include differing developmental trajectories. We conclude by discussing future directions for the field and a brief discussion of biological mechanisms.

Hungry to gamble? Ghrelin as a predictor of persistent gambling in the face of loss

Ghrelin, a peptide hormone associated with appetite, is also linked to increased reward seeking behaviors, including food, sex, and drug seeking behaviors through the stimulation of the mesolimbic dopaminergic system. Moreover, plasma ghrelin concentrations are increased by cues that predict rewards, suggesting that cues could facilitate cravings and ultimately relapse. In this project we examined the effects of an overnight fast, a manipulation known to increase ghrelin concentrations, on gambling behaviors. We also examined if cues associated with gambling would also increase ghrelin and, if so, we examined if these increases were associated with gambling behavior. One hundred and one (37 females) participants were asked to fast overnight or after breakfast and then asked to complete food and gambling craving questionnaires. Participants were then presented with gambling cues (a casino like environment in the lab) or a control cue (a cubicle with a computer). After the cue, subjects filled gambling craving questionnaires, and were allowed to gamble. Following 25 practice spins, the slot machines were fixed so that all subsequent spins were losses, and the number of spins in spite of losses were quantified. Blood samples were collected throughout the experiment. Results showed that the gambling cues significantly increased ghrelin concentrations particularly in fasted individuals, and that ghrelin concentrations 20 min after the cue were the best predictor for gambling persistence in the face of continued loss (p < 0.05). Our results suggest that cues that predict the opportunity to gamble have an acute effect on ghrelin concentrations that is facilitated by fasting, and that ghrelin concentrations are a significant predictor of gambling persistence.

Sex Differences in Risk Preference and c-Fos Expression in Paraventricular Thalamic Nucleus of Rats During Gambling Task

Different biological requirements between males and females may cause sex differences in decision preference when choosing between taking a risk to get a higher gain or taking a lower but sure gain. Several studies have tested this assumption in rats, however the conclusion remains controversial because the previous real-world like gambling tasks contained a learning component to track a global payoff of probabilistic outcome in addition to risk preference. Therefore, we modified a simple gambling task allowing us to exclude such learning effect, and investigated the sex difference in risk preference of rats and its neural basis. The task required water deprived rats to choose between a risky option which provided four drops of water or no reward at a 50% random chance vs. a sure option which provided predictable amount x (x = 1, 2, 3, 4). The amount and the risk were explicitly instructed so that different choice conditions could be tested trial by trial without re-learning of reward contingency. Although both sexes correctly chose the sure option with the same level of accuracy when the sure option provided the best offer (x = 4), they exhibited different choice performances when two options had the same expected value (x = 2). Males and females both preferred to take risky choices than sure choices (risk seeking), but males were more risk seeking than females. Outcome-history analysis of their choice pattern revealed that females reduced their risk preference after losing risky choices, whereas males did not. Rather, as losses continued, reaction time for subsequent risky choices got shorter in males. Given that significant sex difference features mainly emerged after negative experiences, male and female rats may evaluate an unsuccessful outcome of their decision in different manners. Furthermore, c-Fos expression in the paraventricular nucleus of the thalamus (PV) was higher in the gambling task than for the control task in males while c-fos levels did not differ in females. The present study provides a clear evidence of sex differences in risk preference in rats and suggests that the PV is a candidate region contributing to sex differences in risky decision making.

Sex differences in animal models of decision making

The ability to weigh the costs and benefits of various options to make an adaptive decision is critical to an organism's survival and wellbeing. Many psychiatric diseases are characterized by maladaptive decision making, indicating a need for better understanding of the mechanisms underlying this process and the ways in which it is altered under pathological conditions. Great strides have been made in uncovering these mechanisms, but the majority of what is known comes from studies conducted solely in male subjects. In recent years, decision-making research has begun to include female subjects to determine whether sex differences exist and to identify the mechanisms that contribute to such differences. This Mini-Review begins by describing studies that have examined sex differences in animal (largely rodent) models of decision making. Possible explanations, both theoretical and biological, for such differences in decision making are then considered. The Mini-Review concludes with a discussion of the implications of sex differences in decision making for understanding psychiatric conditions. © 2016 Wiley Periodicals, Inc.

Inter-individual differences in decision-making, flexible and goal-directed behaviors: novel insights within the prefronto-striatal networks

Inflexible behavior is a hallmark of several decision-making-related disorders such as ADHD and addiction. As in humans, a subset of healthy rats makes poor decisions and prefers immediate larger rewards despite suffering large losses in a rat gambling task (RGT). They also display a combination of traits reminiscent of addiction, notably inflexible behavior and perseverative responses. The goal of the present work was twofold: (1) to elucidate if behavioral inflexibility of poor decision-makers could be related to a lower quality of goal-directed behavior (action-outcome associations); (2) to uncover the neural basis of inter-individual differences in goal-directed behavior. We specifically assessed inter-individual differences in decision-making in the RGT, flexibility in the RGT-reversed version and goal-directed behavior in a contingency degradation test, i.e., response adaptation when dissociating reward delivery from the animal's action. The contributions of the medial prefrontal cortex and the dorsal striatum to action-outcome associations were assessed using Zif268 immunodetection. Inflexible behavior was related to a lower sensitivity to contingency degradation in all poor decision-makers and only in a few good decision-makers. This poorer sensitivity was associated with a lower immunoreactivity in prelimbic and infralimbic cortices and a higher one in the dorsomedial and dorsolateral striatum. These findings suggest that an imbalanced prefronto-striatal activity could underlie inaccurate goal representation in changing environments and may promote maladaptive habit formation among poor decision-makers. These data strengthen our previous work identifying biomarkers of vulnerability to develop psychiatric disorders and demonstrate the relevance of inter-individual differences to model maladaptive behaviors.

The Blurred Future of Adolescent Gamblers: Impulsivity, Time Horizon, and Emotional Distress

The main purpose of this study was to investigate the interplay of functional and dysfunctional impulsivity, delay discounting, time perspective, and emotional negative states on gambling severity in Italian adolescents. A second aim of the study was to analyze the developmental trajectories of gambling involvement, functional and dysfunctional impulsivity, delay discounting, consideration of future consequences, and negative affectivity in a cross-sectional perspective. One thousand and ten Italian adolescents aging between 12 and 19 years were administered the South Oaks Gambling Screen Revised for Adolescents (SOGS-RA), the Functional and Dysfunctional Impulsivity Scale (FDIS), the Monetary Choice Questionnaire (MCQ), the Consideration of Future Consequences Scale (CFC-14), and the Depression, Anxiety and Stress Scales-21 (DASS-21). Data analyses were conducted using correlational analysis, Chi-square test, analysis of variance, and hierarchical regression analysis. Results indicated that, relative to non-gamblers and non-problem gamblers, at-risk and problem gamblers showed higher levels of impulsivity, steeper delay discounting, shorter time horizon, and reported experiencing significantly higher levels of depression, anxiety, and stress. Results of hierarchical regression analysis, with SOGS-RA scores as the dependent variable, and gender, age, FDIS, MCQ, CFC-14, and DASS-21 scores as independent variables, indicated that, along with gender and age, low scores of future orientation and high scores of dysfunctional impulsivity, depression, anxiety, present orientation, and delay discounting significantly predicted gambling severity. These findings provide further evidence that the higher the gambling involvement, the greater the tendency to devalue delayed rewards and to focus on the immediate consequences of one's behavior. Interestingly, for the first time these results reveal an association between gambling severity and both dysfunctional impulsivity and negative affective states across adolescence. Finally, results of cross-sectional analyses suggest that gambling severity contributes more than age in shaping the developmental trajectories of functional and dysfunctional impulsivity, delay discounting, time perspective, and negative affective states.

An Automated, Experimenter-Free Method for the Standardised, Operant Cognitive Testing of Rats

Animal models of human pathology are essential for biomedical research. However, a recurring issue in the use of animal models is the poor reproducibility of behavioural and physiological findings within and between laboratories. The most critical factor influencing this issue remains the experimenter themselves. One solution is the use of procedures devoid of human intervention. We present a novel approach to experimenter-free testing cognitive abilities in rats, by combining undisturbed group housing with automated, standardized and individual operant testing. This experimenter-free system consisted of an automated-operant system (Bussey-Saksida rat touch screen) connected to a home cage containing group living rats via an automated animal sorter (PhenoSys). The automated animal sorter, which is based on radio-frequency identification (RFID) technology, functioned as a mechanical replacement of the experimenter. Rats learnt to regularly and individually enter the operant chamber and remained there for the duration of the experimental session only. Self-motivated rats acquired the complex touch screen task of trial-unique non-matching to location (TUNL) in half the time reported for animals that were manually placed into the operant chamber. Rat performance was similar between the two groups within our laboratory, and comparable to previously published results obtained elsewhere. This reproducibility, both within and between laboratories, confirms the validity of this approach. In addition, automation reduced daily experimental time by 80%, eliminated animal handling, and reduced equipment cost. This automated, experimenter-free setup is a promising tool of great potential for testing a large variety of functions with full automation in future studies.

Reliability of Instruments Measuring At-Risk and Problem Gambling Among Young Individuals: A Systematic Review Covering Years 2009-2015

This review aims to clarify which instruments measuring at-risk and problem gambling (ARPG) among youth are reliable and valid in light of reported estimates of internal consistency, classification accuracy, and psychometric properties. A systematic search was conducted in PubMed, Medline, and PsycInfo covering the years 2009-2015. In total, 50 original research articles fulfilled the inclusion criteria: target age under 29 years, using an instrument designed for youth, and reporting a reliability estimate. Articles were evaluated with the revised Quality Assessment of Diagnostic Accuracy Studies tool. Reliability estimates were reported for five ARPG instruments. Most studies (66%) evaluated the South Oaks Gambling Screen Revised for Adolescents. The Gambling Addictive Behavior Scale for Adolescents was the only novel instrument. In general, the evaluation of instrument reliability was superficial. Despite its rare use, the Canadian Adolescent Gambling Inventory (CAGI) had a strong theoretical and methodological base. The Gambling Addictive Behavior Scale for Adolescents and the CAGI were the only instruments originally developed for youth. All studies, except the CAGI study, were population based. ARPG instruments for youth have not been rigorously evaluated yet. Further research is needed especially concerning instruments designed for clinical use.

Neuronal Nicotinic Receptors Are Crucial for Tuning of E/I Balance in Prelimbic Cortex and for Decision-Making Processes

RATIONALE

Decision-making is an essential component of our everyday life commonly disabled in a myriad of psychiatric conditions, such as bipolar and impulsive control disorders, addiction and pathological gambling, or schizophrenia. A large cerebral network encompassing the prefrontal cortex, the amygdala, and the nucleus accumbens is activated for efficient decision-making.

METHODS

We developed a mouse gambling task well suited to investigate the influence of uncertainty and risk in decision-making and the role of neurobiological circuits and their monoaminergic inputs. Neuronal nicotinic acetylcholine receptors (nAChRs) of the PFC are important for decision-making processes but their presumed roles in risk-taking and uncertainty management, as well as in cellular balance of excitation and inhibition (E/I) need to be investigated.

RESULTS

Using mice lacking nAChRs - β2^-/- mice, we evidence for the first time the crucial role of nAChRs in the fine tuning of prefrontal E/I balance together with the PFC, insular, and hippocampal alterations in gambling behavior likely due to sensitivity to penalties and flexibility alterations. Risky behaviors and perseveration in extinction task were largely increased in β2^-/- mice as compared to control mice, suggesting the important role of nAChRs in the ability to make appropriate choices adapted to the outcome.

Sex differences in a rat model of risky decision making

Many debilitating psychiatric conditions, including drug addiction, are characterized by poor decision making and maladaptive risk-taking. Recent research has begun to probe this relationship to determine how brain mechanisms mediating risk-taking become compromised after chronic drug use. Currently, however, the majority of work in this field has used male subjects. Given the well-established sex differences in drug addiction, it is conceivable that such differences are also evident in risk-based decision making. To test this possibility, male and female adult rats were trained in a risky decision making task (RDT), in which they chose between a small, "safe" food reward and a large, "risky" food reward accompanied by an increasing probability of mild footshock punishment. Consistent with findings in human subjects, females were more risk averse, choosing the large, risky reward significantly less than males. This effect was not due to differences in shock reactivity or body weight, and risk-taking in females was not modulated by estrous phase. Systemic amphetamine administration decreased risk-taking in both males and females; however, females exhibited greater sensitivity to amphetamine, suggesting that dopaminergic signaling may partially account for sex differences in risk-taking. Finally, although males displayed greater instrumental responding for food reward, reward choice in the RDT was not affected by satiation, indicating that differences in motivation to obtain food reward cannot fully account for sex differences in risk-taking. These results should prove useful for developing targeted treatments for psychiatric conditions in which risk-taking is altered and that are known to differentially affect males and females.

A test of stress, cues, and re-exposure to large wins as potential reinstaters of suboptimal decision making in rats

The present experiment investigated potential reinstaters of suboptimal economic decision making in rats. Rats were first trained on a version of the rat Gambling Task under conditions designed to promote choice of a suboptimal option that occasionally resulted in large “wins” (four sucrose pellets). In a second phase, preference for this economically suboptimal option was reduced by substantially increasing the probability of punishment when this option was chosen. Then, three events were tested for their ability to reinstate choice of the suboptimal option. A brief period of re-exposure to a high frequency of large wins significantly increased choice of the suboptimal option. The pharmacological stressor yohimbine did not reinstate suboptimal choice, but did increase impulsive action as indexed by premature responding. Presentation of cues previously associated with large wins did not alter behavior. Results suggest reinstaters of suboptimal choice may differ from reinstaters of extinguished drug- and food-seeking behavior.

Ecological momentary assessment in the investigation of craving and substance use in daily life: a systematic review

BACKGROUND

Craving is viewed as a major determinant of relapse in persons with substance addiction, but this association remains poorly understood due to its time-limited nature and the biases associated with retrospective reporting. Ecological momentary assessment (EMA) offers new opportunities to examine both craving and substance use with strong ecological validity by collecting real-time data in daily life. This review examined all published studies using EMA to: (1) assess the link between craving and substance use; and (2) identify relevant moderators of craving among substance users.

METHODS

We searched PubMed and PsycInfo databases up to October 31, 2013.

RESULTS

Ninety-one studies were selected, involving mostly tobacco smokers (73%). A majority of studies (92%) reported a positive relationship between craving and substance use, concurrently and prospectively, and among users with different levels of use for both legal and illegal substances. Results suggest that craving is a stronger predictor of relapse episodes when assessed in close temporal proximity to substance use. EMA data also confirmed the influence of diverse within-person and between-person sources of variation in daily life craving reports.

CONCLUSIONS

This review provides strong support for the link between craving and substance use, and underscores the importance of the timing of assessments.

Body weight status, eating behavior, sensitivity to reward/punishment, and gender: relationships and interdependencies

Behavioral and personality characteristics are factors that may jointly regulate body weight. This study explored the relationship between body mass index (BMI) and self-reported behavioral and personality measures. These measures included eating behavior (based on the Three-Factor Eating Questionnaire; Stunkard and Messick, 1985), sensitivity to reward and punishment (based on the Behavioral Inhibition System/Behavioral Activation System (BIS/BAS) scales) (Carver and White, 1994) and self-reported impulsivity (based on the Barratt Impulsiveness Scale-11; Patton et al., 1995). We found an inverted U-shaped relationship between restrained eating and BMI. This relationship was moderated by the level of disinhibited eating. Independent of eating behavior, BIS and BAS responsiveness were associated with BMI in a gender-specific manner with negative relationships for men and positive relationships for women. Together, eating behavior and BIS/BAS responsiveness accounted for a substantial proportion of BMI variance (men: ∼25%, women: ∼32%). A direct relationship between self-reported impulsivity and BMI was not observed. In summary, our results demonstrate a system of linear and non-linear relationships between the investigated factors and BMI. Moreover, body weight status was not only associated with eating behavior (cognitive restraint and disinhibition), but also with personality factors not inherently related to an eating context (BIS/BAS). Importantly, these relationships differ between men and women.

An 8-week stress management program in pathological gamblers: a pilot randomized controlled trial

Stress plays a major role at the onset and relapse of pathological gambling (PG), but at the same time it can also be the aftermath of gambling behavior, thus revealing a reciprocal relationship. Although the role of stress has been well-documented, there is a paucity of studies investigating the effect of an adjunctive stress management program on PG. In this 8-week parallel randomized waitlist controlled trial pathological gamblers, already in the gamblers anonymous (GA) group, were assigned randomly in two groups, with the intervention group (n = 22) receiving an additional stress management program (consisting of education on diet and exercise, stress coping methods, relaxation breathing -RB- and progressive muscle relaxation -PMR). Self-reported measures were used in order to evaluate stress, depression, anxiety, sleep quality/disturbances, life-satisfaction and daily routine. The statistical analyses for the between group differences concerning the main psychosocial study outcomes revealed a statistically significant amelioration of stress, depression, anxiety symptoms and an increase of life-satisfaction and a better daily routine in participants of the intervention group. We hope that these will encourage researchers and clinicians to adopt stress management in their future work.

Prefronto-subcortical imbalance characterizes poor decision-making: neurochemical and neural functional evidences in rats

A major challenge of decision-making research in recent years has been to develop models of poor decision-making to identify its neural bases. Toward this goal, we developed a Rat Gambling Task that discerns good and poor decision-makers in a complex and conflicting situation such as the human Iowa Gambling Task. Nothing is known about the role of the monoaminergic modulatory systems in shaping these phenotypes. Moreover, functional and temporal contributions of brain areas during poor compared to good decision-making remains elusive. Good and poor decision-makers were identified in the Rat Gambling Task. We investigated neurobiological correlates of decision-making capacities in (1) dopamine and serotonin turnovers using post-mortem tissue measurements, (2) the neural circuits differentially recruited during decision-making within the prefronto-subcortical network using cellular Fos immunodetection. Imbalance in monoamine metabolism was revealed in poor decision-makers, i.e. a higher infralimbic vs. lower amygdala serotonergic metabolism. Moreover, good decision-making recruited a wide prefronto-subcortical network but once good choices had been made, a disengagement of key prefrontal areas (insular and infralimbic cortices notably) and the amygdala was observed. By contrast, poor decision-making was associated with a strikingly low recruitment of the prefronto-subcortical network, together with sustained amygdala activity. Our results identify two complementary neurobiological substrates characterizing poor decision-makers: imbalanced monoaminergic systems at rest, congruent with their previously identified complex behavioral phenotype, and an aberrant low recruitment of key brain areas for executive functions and affective valence during the process of decision-making. These biomarkers could sustain vulnerability to developing poor decision-making related disorders.

Individual differences in gambling proneness among rats and common marmosets: an automated choice task

Interest is rising for animal modeling of pathological gambling. Using the operant probabilistic-delivery task (PDT), gambling proneness can be evaluated in laboratory animals. Drawing a comparison with rats, this study evaluated the common marmoset (Callithrix jacchus) using a PDT. By nose- or hand-poking, subjects learnt to prefer a large (LLL, 5-6 pellets) over a small (SS, 1-2 pellets) reward and, subsequently, the probability of occurrence of large-reward delivery was decreased progressively to very low levels (from 100% to 17% and 14%). As probability decreased, subjects showed a great versus little shift in preference from LLL to SS reinforcer. Hence, two distinct subpopulations (“non-gambler” versus “gambler”) were differentiated within each species. A proof of the model validity comes from marmosets' reaction to reward-delivery omission. Namely, depending on individual temperament (“gambler” versus “non-gambler”), they showed either persistence (i.e., inadequate pokes towards LLL) or restlessness (i.e., inadequate pokes towards SS), respectively. In conclusion, the marmoset could be a suitable model for preclinical gambling studies. Implementation of the PDT to species other than rats may be relevant for determining its external validity/generalizability and improving its face/construct validity.

Risk-taking and pathological gambling behavior in Huntington's disease

Huntington's disease (HD) is a genetic, neurodegenerative disorder, which specifically affects striatal neurons of the indirect pathway, resulting in a progressive decline in muscle coordination and loss of emotional and cognitive control. Interestingly, predisposition to pathological gambling and other addictions involves disturbances in the same cortico-striatal circuits that are affected in HD, and display similar disinhibition-related symptoms, including changed sensitivity to punishments and rewards, impulsivity, and inability to consider long-term advantages over short-term rewards. Both HD patients and pathological gamblers also show similar performance deficits on risky decision-making tasks, such as the Iowa Gambling Task (IGT). These similarities suggest that HD patients are a likely risk group for gambling problems. However, such problems have only incidentally been observed in HD patients. In this review, we aim to characterize the risk of pathological gambling in HD, as well as the underlying neurobiological mechanisms. Especially with the current rise of easily accessible Internet gambling opportunities, it is important to understand these risks and provide appropriate patient support accordingly. Based on neuropathological and behavioral findings, we propose that HD patients may not have an increased tendency to seek risks and start gambling, but that they do have an increased chance of developing an addiction once they engage in gambling activities. Therefore, current and future developments of Internet gambling possibilities and related addictions should be regarded with care, especially for vulnerable groups like HD patients.

Endogenous cortisol levels are associated with an imbalanced striatal sensitivity to monetary versus non-monetary cues in pathological gamblers

Pathological gambling is a behavioral addiction characterized by a chronic failure to resist the urge to gamble. It shares many similarities with drug addiction. Glucocorticoid hormones including cortisol are thought to play a key role in the vulnerability to addictive behaviors, by acting on the mesolimbic reward pathway. Based on our previous report of an imbalanced sensitivity to monetary versus non-monetary incentives in the ventral striatum of pathological gamblers (PGs), we investigated whether this imbalance was mediated by individual differences in endogenous cortisol levels. We used functional magnetic resonance imaging (fMRI) and examined the relationship between cortisol levels and the neural responses to monetary versus non-monetary cues, while PGs and healthy controls were engaged in an incentive delay task manipulating both monetary and erotic rewards. We found a positive correlation between cortisol levels and ventral striatal responses to monetary versus erotic cues in PGs, but not in healthy controls. This indicates that the ventral striatum is a key region where cortisol modulates incentive motivation for gambling versus non-gambling related stimuli in PGs. Our results extend the proposed role of glucocorticoid hormones in drug addiction to behavioral addiction, and help understand the impact of cortisol on reward incentive processing in PGs.

A rodent version of the Iowa Gambling Task: 7 years of progress

In the Iowa Gambling Task (IGT) subjects need to find a way to earn money in a context of variable wins and losses, conflicting short-term and long-term pay-off, and uncertainty of outcomes. In 2006, we published the first rodent version of the IGT (r-IGT; Behavior Research Methods 38, 470–478). Here, we discuss emerging ideas on the involvement of different prefrontal-striatal networks in task-progression in the r-IGT, as revealed by our studies thus far. The emotional system, encompassing, among others, the orbitofrontal cortex, infralimbic cortex and nucleus accumbens (shell and core area), may be involved in assessing and anticipating the value of different options in the early stages of the task, i.e., as animals explore and learn task contingencies. The cognitive control system, encompassing, among others, the prelimbic cortex and dorsomedial striatum, may be involved in instrumental goal-directed behavior in later stages of the task, i.e., as behavior toward long-term options is strengthened (reinforced) and behavior toward long-term poor options is weakened (punished). In addition, we suggest two directions for future research: (1) the role of the internal state of the subject in decision-making, and (2) studying differences in task-related costs. Overall, our studies have contributed to understanding the interaction between the emotional system and cognitive control system as crucial to navigating human and non-human animals alike through a world of variable wins and losses, conflicting short-term and long-term pay-offs, and uncertainty of outcomes.

Nonhuman gamblers: lessons from rodents, primates, and robots

The search for neuronal and psychological underpinnings of pathological gambling in humans would benefit from investigating related phenomena also outside of our species. In this paper, we present a survey of studies in three widely different populations of agents, namely rodents, non-human primates, and robots. Each of these populations offers valuable and complementary insights on the topic, as the literature demonstrates. In addition, we highlight the deep and complex connections between relevant results across these different areas of research (i.e., cognitive and computational neuroscience, neuroethology, cognitive primatology, neuropsychiatry, evolutionary robotics), to make the case for a greater degree of methodological integration in future studies on pathological gambling.

Salivary cortisol and alpha-amylase levels during an assessment procedure correlate differently with risk-taking measures in male and female police recruits

Recent laboratory studies have shown that men display more risk-taking behavior in decision-making tasks following stress, whilst women are more risk-aversive or become more task-focused. In addition, these studies have shown that sex differences are related to levels of the stress hormone cortisol (indicative of activation of the hypothalamus-pituitary-adrenocortical-axis): the higher the levels of cortisol the more risk-taking behavior is shown by men, whereas women generally display more risk-aversive or task-focused behavior following higher levels of cortisol. Here, we assessed whether such relationships hold outside the laboratory, correlating levels of cortisol obtained during a job-related assessment procedure with decision-making parameters in the Cambridge Gambling Task (CGT) in male and female police recruits. The CGT allows for discriminating different aspects of reward-based decision-making. In addition, we correlated levels of alpha-amylase [indicative of activation of the sympatho-adrenomedullary-axis (SAM)] and decision-making parameters. In line with earlier studies men and women only differed in risk-adjustment in the CGT. Salivary cortisol levels correlated positively and strongly with risk-taking measures in men, which was significantly different from the weak negative correlation in women. In contrast, and less strongly so, salivary alpha-amylase levels correlated positively with risk-taking in women, which was significantly different from the weak negative correlation with risk-taking in men. Collectively, these data support and extend data of earlier studies indicating that risky decision-making in men and women is differently affected by stress hormones. The data are briefly discussed in relation to the effects of stress on gambling.