Psychiatry. Behavioral addictions debut in proposed DSM-V

Rats Lacking the Dopamine Transporter Display Inflexibility in Innate and Learned Behavior

Playing a key role in the organization of striatal motor output, the dopamine (DA)-ergic system regulates both innate and complex learned behaviors. Growing evidence clearly indicates the involvement of the DA-ergic system in different forms of repetitive (perseverative) behavior. Some of these behaviors accompany such disorders as obsessive-compulsive disorder (OCD), Tourette's syndrome, schizophrenia, and addiction. In this study, we have traced how the inflexibility of repetitive reactions in the recently developed animal model of hyper-DA-ergia, dopamine transporter knockout rats (DAT-KO rats), affects the realization of innate behavior (grooming) and the learning of spatial (learning and reversal learning in T-maze) and non-spatial (extinction of operant reaction) tasks. We found that the microstructure of grooming in DAT-KO rats significantly differed in comparison to control rats. DAT-KO rats more often demonstrated a fixed syntactic chain, making fewer errors and very rarely missing the chain steps in comparison to control rats. DAT-KO rats' behavior during inter-grooming intervals was completely different to the control animals. During learning and reversal learning in the T-maze, DAT-KO rats displayed pronounced patterns of hyperactivity and perseverative (stereotypical) activity, which led to worse learning and a worse performance of the task. Most of the DAT-KO rats could not properly learn the behavioral task in question. During re-learning, DAT-KO rats demonstrated rigid perseverative activity even in the absence of any reinforcement. In operant tasks, the mutant rats demonstrated poor extinction of operant lever pressing: they continued to perform lever presses despite no there being reinforcement. Our results suggest that abnormally elevated DA levels may be responsible for behavioral rigidity. It is conceivable that this phenomenon in DAT-KO rats reflects some of the behavioral traits observed in clinical conditions associated with endogenous or exogenous hyper-DA-ergia, such as schizophrenia, substance abuse, OCD, patients with Parkinson disease treated with DA mimetics, etc. Thus, DAT-KO rats may be a valuable behavioral model in the search for new pharmacological approaches to treat such illnesses.

Is online shopping addiction still a depressive illness? -- the induced consumption and traffic trap in live E-commerce

While immersive shopping has injected new vitality into China's e-commerce, it has also resulted in consumers' over-reliance on online shopping. Psychological studies have linked online shopping addiction with depression, but business practices challenge this conclusion. This study, grounded in addiction theory, developed a theoretical model, and conducted an online survey with 214 live-streaming shoppers using structural equation modeling for validation. The primary focus was on determining whether consumers truly become addicted to online shopping in the four stages of the addiction model. The study unveils the process of consumers becoming addicted to online shopping. It explores the moderating role of perceived risk in the relationship between utilitarian and hedonic purchases and online shopping addiction. The findings suggest that through tactics such as traffic promotion, traffic trapping, anchor feature utilization, and incorporation of consumer aesthetics, merchants may induce utilitarian and hedonic purchases, leading to addiction to live-streaming shopping among consumers. Furthermore, perceived risk significantly and negatively moderates the relationship between utilitarian purchases and online shopping addiction. Our research indicates that merchants intentionally create external stimuli, enticing consumers to indulge in online shopping, suggesting that online shopping addiction is not merely a simple psychological state but may be influenced by external factors. This study provides novel insights into the phenomenon of online shopping addiction while offering valuable recommendations for consumers seeking to avoid succumbing to its allure.

Engineered highs: Reward variability and frequency as potential prerequisites of behavioural addiction

Influential learning-based accounts of substance addictions posit the attribution of incentive salience to drug-associated cues, and its escalation by the direct dopaminergic effects of drugs. In translating this account to disordered gambling, we have noted how the intermittent nature of monetary rewards in gambling (i.e. the variable ratio) may allow for analogous learning processes, via effects on dopaminergic signalling. The aim of the present article is to consider how multiple sources of reward variability operate within modern gambling products, and how similar sources of variability, as well as some novel sources of variability, also apply to other digital products implicated in behavioural addictions, including gaming, shopping, social media and online pornography. Online access to these activities facilitates not only unparalleled accessibility but also introduces novel forms of reward variability, as seen in the effects of infinite scrolls and personalized recommendations. We use the term uncertainty to refer to the subjective experience of reward variability. We further highlight two psychological factors that appear to moderate the effects of uncertainty: 1) the timecourse of uncertainty, especially with regard to its resolution, 2) the frequency of exposure, allowing temporal compression. Collectively, the evidence illustrates how qualitative and quantitative variability of reward can confer addictive potential to non-drug reinforcers by exploiting the psychological and neural processes that rely on predictability to guide reward seeking behaviour.

Internet gaming disorder and tobacco use disorder share neural connectivity patterns between the subcortical and the motor network

Internet gaming disorder (IGD) and tobacco use disorder (TUD) are globally common, non-substance-related disorders and substance-related disorders worldwide, respectively. Recognizing the commonalities between IGD and TUD will deepen understanding of the underlying mechanisms of addictive behavior and excessive online gaming. Using node strength, 141 resting-state data were collected in this study to compute network homogeneity. The participants included participants with IGD (PIGD: n = 34, male = 29, age: 15-25 years), participants with TUD (PTUD: n = 33, male = 33, age: 19-42 years), and matched healthy controls (control-for-IGD: n = 41, male = 38, age: 17-32 years; control-for-TUD: n = 33, age: 21-27 years). PIGD and PTUD exhibited common enhanced node strength between the subcortical and motor networks. Additionally, a common enhanced resting-state functional connectivity (RSFC) was found between the right thalamus and right postcentral gyrus in PIGD and PTUD. Node strength and RSFC were used to distinguish PIGD and PTUD from their respective healthy controls. Interestingly, models trained on PIGD versus controls could classify PTUD versus controls and vice versa, suggesting that these disorders share common neurological patterns. Enhanced connectivity may indicate a greater association between rewards and behaviors, inducing addiction behaviors without flexible and complex regulation. This study discovered that the connectivity between the subcortical and motor networks is a potential biological target for developing addiction treatment in the future.

Mental illness and socio-economic situation of women and men diagnosed with gambling disorder (GD) in Sweden - nationwide case-control study

The present study aimed to compare men and women with gambling disorder (GD) regarding presence of psychiatric comorbidity and socio-economic vulnerability, and to examine whether these factors appear before or after the gambling disorder. This is a retrospective case-control study, based on registers from The National Board of Health and Welfare and Statistics Sweden. A total of 3592 adults with GD were matched with two controls based on age and gender, including a total of 10776 individuals in the study. The study included psychiatric comorbidity through the presence of relevant diagnostic codes or pharmacological codes, and socio-economic vulnerability data through the presence of unemployment, social welfare payments and sickness/activity/rehabilitation compensation. Time between GD and psychiatric comorbidity/socio-economic vulnerability was calculated by subtracting dates between diagnoses/first incidence of socio-economic vulnerability factor and GD diagnosis. Women with GD were more likely to have a psychiatric comorbidity, compared to men. Overall, women were also more likely to receive their psychiatric diagnosis prior to GD diagnosis, while men were more likely to receive the diagnoses concurrently. Social welfare payments, and sickness support were more common among women, while there was no difference in unemployment between genders. Women were also more likely to receive sickness/activity/rehabilitation compensation prior to GD, than men who were more likely to receive these types of support after GD diagnosis. In conclusion, women appear to be at higher risk of psychiatric comorbidity and socio-economic vulnerability alongside GD. They are in general also more likely to receive have their psychiatric and psycho-social problems identified prior to GD, than men who are more likely to receive diagnoses concurrently.

Behavioral Addictions Questionnaire (BAQ): Validation of a New Tool for the Screening of Multiple Addictive Behaviors in the Italian Population

This study deals with the uncertainty in defining behavioral addictions (BAs). BAs are characterized by specific compulsive behaviors, regardless of potential negative consequences. However, to differentiate a behavior from a leisure activity to an addictive one is still an object of debate in the literature. Accordingly, this study aimed to assess the psychometric properties of the Behavioral Addictions Questionnaire (BAQ) as a possible screening tool for multiple BAs (i.e., shopping, food addiction, gambling, sex, work, exercise, Internet, videogames, and smartphone). BAQ aims to give a dimensional and quantitative assessment of addictive behaviors in a continuum, including both the adaptive and maladaptive features of the behaviors. Five hundred and seventy-six healthy adults (age range: 18–88) participated in the study, completing a survey including the BAQ questionnaire. Considering both exploratory and confirmatory factor analyses, statistical examination suggested good psychometric properties, with adequate validity in all its subscales (i.e., the goodness of fit). Moreover, also higher reliability was confirmed for each dimension detected (i.e., all alpha over 0.65). The BAQ represents a comprehensive screening instrument that benefits from appropriate validity and reliability for assessing BAs. Therefore, it can be used in clinical fields and research. Moreover, the feature of BAs on a continuum, and the severity index adopted by the study, can help from a preventive perspective. However, further validation of the BAQ is needed in other countries and contexts.

Problematic use of digital media in children and adolescents with a diagnosis of attention-deficit/hyperactivity disorder compared to controls. A meta-analysis

Objective

Problematic use of digital media and problematic use of the internet (PUI) in particular are growing problems in the general population. Moreover, studies have shown links between PUI and symptoms of attention-deficit/hyperactivity disorder (ADHD). This meta-analysis investigated whether children and adolescents with ADHD are more often affected by PUI compared to control groups.

Method

Multiple databases (EBSCOhost, Pubmed) were reviewed. Studies were eligible if individuals (aged 6-18 years) were diagnosed with ADHD, assessed on PUI-related measures, and compared to non-clinical or/and clinical controls without a diagnosis of ADHD. Out of 3,859 identified studies, 14 studies assessing 2,488 participants met all inclusion criteria. Four meta-analyses examining time-based and scale-based measures, different informants and non-clinical vs. clinical controls using random-effects models were performed. Funnel plots were used to investigate publication bias.

Results

The analyses revealed significantly more severe PUI in individuals with ADHD compared to controls, both when PUI was assessed via rating scale (scaled-based) and via units for time (time-based measures). Different informants (self- vs. parent-rating) had no impact on results. Differences in PUI between groups with ADHD and non-clinical controls were significant, whereas differences between ADHD and clinical controls were not. Due to the high heterogeneity observed and the small sample sizes, these latter findings should be interpreted cautiously.

Conclusion

Children and adolescents with ADHD show more severe PUI compared to non-clinical controls without ADHD. However, the small number of studies does not allow for a systematic comparison between ADHD and groups with other psychopathologies.

Novel approaches for treating Internet Gaming Disorder: A review of technology-based interventions

Internet Gaming Disorder (IGD) has become a significant issue in mental healthcare over the past decades as the number of people engaging in excessive and unhealthy gaming increases with each year. Despite its inclusion in the 5th Edition of Diagnostic Statistical Manual and the development of a number of treatment methods that have been designed and tested for IGD, treatment remains a challenge. This review attempts to give an overview of the current state of IGD and its treatment with a specific focus on the potential of technology-based solutions, such as web-based programs, mobile applications, and virtual reality. The review also highlights the need for additional work in the area of treatment development for IGD and the preliminary evidence for the usefulness and importance of technology-based treatment methods which offer unique advantages, such as accessibility, scalability, and cost-effectiveness, over other existing treatment options.

Prevalence and Factors Associated with Problematic Internet Use in a Population of Spanish University Students

(1) Background: To examine the prevalence, and associated factors of, problematic Internet use in a sample of Spanish university students. (2) Methods: Cross-sectional descriptive study of a convenience sample of 698 university students. Self-esteem, alcohol consumption, perceived social support, depression, anxiety, stress and problematic Internet use were evaluated using the Rosenberg, CAGE, DUKE-UNC-11, DASS-21 and Young's Internet Addiction Test, respectively. (3) Results: Problematic internet use was reported by 21% of respondents. Risk of problematic Internet use was independently associated with the preferred use of the smartphone, time of exposure to the Internet, less perceived social support, problematic alcohol consumption and symptoms of stress and anxiety. We found significant association between problematic internet use and time of exposure to the Internet, residential status, alcohol consumption, self-esteem, perceived social support and psychological distress, after bivariate analysis. (4) Conclusions: A considerable prevalence of problematic Internet use was found; in our sample problematic Internet use was associated with stress, alcohol consumption, anxiety and perceived social support. Strategies aimed at the early identification of problematic Internet use may lead to an improvement in the psychosocial health of the university student population.

Impulsivity, Consciousness and Defense Mechanisms of the Ego Among Pathological Gamblers

Pathological gambling is a growing health problem in Romania, recognized in DSM V (2013) as a form of psychopathology included in the category of addictions. This study aims to find out whether there are differences between gamblers and the control group among the dependent variables (impulsivity, conscientiousness, and defense mechanisms). According to the literature, impulsivity and low conscientiousness are specific features to pathological gamblers. A second goal is to check if there are one or more defense mechanisms defining gamblers. A recent study (Waqas et al., Waqas et al., Psychiatry Research 243:463-468, 2016) about the association of defense mechanisms and the problematic use of the Internet identified the following defense mechanisms: projection, denial, passive aggression, and movement. The present study questionnaire consists of four sections: a) The impulsivity questionnaire (Eysenk et al., Eysenck et al., Personality and Individual Differences 6:613-619, 1985), b) Defense Style Questionnaire-40, c) C-NEO (only the items related to the Conscientiousness factor) and d) SOGS (South Oaks Gambling Screen) test. This questionnaire was applied to 40 gamblers in the full version, and the control group was given the same questionnaire apart from the SOGS test. All data were analyzed in SPSS v20. The research results show that pathological gamblers have higher impulsivity than the control group, their defense mechanisms are predominantly neurotic and immature and their conscientiousness is significantly lower than the control group.

Internet Addiction, Sleep Quality and Depressive Symptoms Amongst Medical Students in Delhi, India

Today, the internet has become an important element in people's lives, and owing to internet access becoming widespread, it has resulted in internet addiction. It is a major concern amongst medical students aiming to develop into health professionals. The implications of this addiction as well as its association with sleep and depression affects their studies, impacts their career goals and has detrimental consequences for society as a whole. The objectives of this study were to assess the proportion of medical undergraduate students and interns with internet addiction (IA), depressive symptoms and poor sleep quality and to study the association of IA with sleep quality and depressive symptoms. A cross-sectional questionnaire-based study was carried out in a medical college in Delhi. Universal sample consisting of all the medical students from first to final year (n = 185) and interns (n = 37) enrolled during the time of the study were included. Sleep quality, internet addiction and depressive symptoms in these students was assessed using Pittsburgh Sleep Quality Index (PSQI) Young's Internet Addiction Test (YIAT) and Patient Health Questionnaire-9 (PHQ) respectively. The average YIAT score was 33.16 ± 15.68. Overall 18%, 59.9%, 46.8% of students scored above validated cutoff scores for internet addiction, poor sleep quality and depression respectively. Prevalence of IA among males and females were 20.4% and 12.9% respectively. Significant correlations were found between potential IA, sleep quality and depression (p < 0.001). The study concluded a strong correlation between IA, disturbed sleep quality and depression. Identifying medical students with potential IA is important because this addiction often coexists with other psychological problems. Thus timely remedial actions and tailored interventions are required to combat IA among medical students.

Does the smartphone use affect the determination of daily goals: A nursing students' example?

PURPOSE

To examine how the risky use of smartphone in nursing students affects their daily goals.

DESIGN AND METHODS

A total of 419 nursing students participated in this study. A Descriptive Data Form, Smartphone Addiction Scale-Short Version, and Daily Goals Scale were used to collect the data.

FINDINGS

According to our study results; students who are afraid of forgetting or losing their phone have a higher risk of being smartphone addiction. As the risks of students' smartphone addiction increase, their daily goal setting levels decreased.

PRACTICE IMPLICATIONS

The risky use of smartphone effects negatively daily goals setting. Education and counseling programs that will prevent the risky use of smartphones and the associated risk of addiction should be provided for nursing students.

The Development of the Turkish Craving for Online Shopping Scale: A Validation Study

In the present study, the Turkish version of the Craving for Online Shopping Scale (TCOSS) was developed by modifying items on the Penn Alcohol Craving Scale (PACS). The sample comprised 475 adult volunteers (233 women and 242 men) from three different non-clinical samples recruited online. The structure validity of the TCOSS was examined utilizing exploratory factor analysis (EFA), confirmatory factor analysis (CFA), and criterion validity testing. The EFA showed that the TCOSS had a unidimensional structure that explained 80% of the total variance. The five-item unidimensional structure of the TCOSS then underwent further testing using two different samples. First, the structure of the TCOSS was tested using CFA, which confirmed the unidimensional factor structure. Second, measurement invariance of the TCOSS was conducted through structural invariance, metric invariance, and scalar invariance across different samples. This demonstrated the TCOSS had measurement invariance across different samples (CFA and criterion validity samples). Criterion validity of the TCOSS was tested using the Internet Addiction Test-Short Form, Brief Self-Control Scale, Compulsive Online Shopping Scale, Positive and Negative Affect Schedule, and self-reported personal information. According to the criterion validity results, the TCOSS assessed the structure it targets. Cronbach’s α internal consistency coefficients of the TCOSS were .94 in the EFA sample, .94 in the CFA sample, and .96 in the criterion validity sample. When validity and reliability analysis of the TCOSS are considered as a whole, it is concluded that the TCOSS is a valid and reliable scale for assessing craving for online shopping among online shoppers.

Traumatic brain injury as an independent risk factor for problem gambling: a matched case-control study

PURPOSE

To assess whether traumatic brain injury (TBI) increases the risks of subsequent problem gambling.

METHODS

We conducted a matched case-control analysis of adults in Ontario, Canada. The study included those who self-reported their gambling activities in the Canadian Community Health Survey 2007-2008. Using Problem Gambling Severity Index, we defined cases as those who were problem gamblers and controls who were recreational gamblers. Cases were matched to controls 1:2 using propensity scores based on demographics, prior mental health, and self-reported behaviours. The main predictor was prior TBI defined as requiring emergency care and identified using ICD-10 codes from administrative health databases. We estimated the likelihood of prior TBI in problem gamblers compared to controls using conditional logistic regression.

RESULTS

Of 30,652 survey participants, 16,002 (53%) reported gambling activity of whom 14,910 (49%) were recreational gamblers and 4% (n = 1092) were problem gamblers. A total of 1469 respondents (5%) had a prior TBI. Propensity score matching yielded 2038 matched pairs with 1019 cases matched to 2037 controls. Case-control analysis showed a significant association between prior TBI and subsequent problem gambling (odds ratio 1.27, 95% confidence interval 1.07-1.51, P = 0.007). The increased risk was mostly apparent in men aged 35 to 64 years who reported alcohol use or smoking. The relative risk of problem gambling in those with two or more TBIs equated to an odds ratio of 2.04 (95% confidence interval 1.05-3.99).

CONCLUSIONS

We found that a prior TBI was associated with an increased subsequent risk of problem gambling. Our findings support more awareness, screening, and treating problem gambling risks among TBI patients.

Assessing the Psychometric Properties of the Internet Addiction Test (IAT) Among Lebanese College Students

Internet addiction is an emergent problem; yet, both a strong conception of the factors precipitating challenging activities and a gold standard tool for evaluating symptoms are deficient. The aim of this study was to carry out a psychometric analysis using the most commonly employed screening tool, the young Internet Addiction Test (IAT), comprising a sample of Lebanese University medical students. Two hundred and fifty-six undergraduate medical students from a university in Beirut, Lebanon were included in our IAT. Exploratory factor analysis was employed, and four factors were extracted. These four factors were named as Lack of Control, Social Withdrawal and Emotional Conflict, Time Management Problems, and Concealing Problematic Behavior. Furthermore, the selected factors explained 56.5% of the total variance. Cronbach's alpha coefficient for the internal reliability of the scale was found to be 0.91. For each subscale, the internal consistency score was approximated and detected as 0.76, 0.74, 0.69, and 0.63 for the first through fourth factor, respectively. Item total correlations were calculated and had a value range from 0.37 to 0.63 for the 20 items. IAT is a proper tool for evaluating internet addiction in Lebanese college students.

Examining Factors Influencing Internet Addiction and Adolescent Risk Behaviors Among Excessive Internet Users

In China, public concern continues to mount regarding the risks of excessive Internet use among adolescents. This study investigated the factors influencing Internet addiction and adolescent risk behaviors among excessive Internet users. Proposing a conceptual model with a theoretical origin in risk behavior theory and media dependency theory, this study examined the influence of personality traits, online gaming, Internet connectedness (both the overall index and various scopes), and demographics on Internet addiction and risk behaviors (smoking, drinking, gambling, and risky sexual behaviors). Clinical data (N = 467) were retrieved from one of the earliest and largest Internet addiction clinics in China. The findings reveal that certain personality traits are significantly associated with Internet addiction and risk behaviors. Online gaming had a strong impact on both Internet addiction and risk behaviors among excessive Internet users. The study also reveals that various scopes of Internet connectedness, such as site scope, facilitate addictive Internet use, and risk behaviors among adolescents. The findings can contribute to the prevention of and intervention into Internet addiction and adolescent risk behaviors.

Drug-induced gambling disorder: A not so rare but underreported condition

The widespread use of dopaminergic agents for the treatment of Parkinson's disease has revealed the presence of gambling disorder (GD) as an uncommon, but serious, adverse reaction to these agents. We describe the main characteristics of drug-induced GD reports received by the Spanish Pharmacovigilance System during the period from 1983 to 2016. Fifteen reports of GD have been identified. Dopaminergic agonists, especially pramipexole, are the main drugs involved in inducing GD. Physicians prescribing these drugs should warn patients and families about this disorder. Knowledge of this disorder will encourage early diagnosis, treatment, and reporting of this clinically and socially relevant disorder.

Internet addiction among social networking sites users: Emerging mental health concern among medical undergraduates of Karachi

Objective:

To determine the frequency and intensity of Internet Addiction (IA) among medical undergraduates, using Social Networking Sites (SNS), in Karachi.

Methods:

A cross-sectional survey was conducted in March-June ‘16 in a private and government medical college of Karachi. Self-administered, Young’s Internet Addiction Test was implemented by 340 medical students to assess the frequency and intensity of IA among SNS profile users for past three years. The structured questionnaire further enquired regarding the social and behaviour patterns relevant to IA and SNS use. Data was analyzed using SPSS 16.

Results:

Internet Addiction (IA) was found in 85% (n=289) of all study participants. Among them, 65.6% (n=223) were ‘minimally addicted’, 18.5% (n=63) were ‘moderately addicted’, whereas 0.9% (n=3) were found to be ‘severely addicted’. Burden of IA was relatively higher among female medical students as compared to male medical students (p=0.02). There was no significant difference between type of medical college attended and IA (p=0.45). However, statistically significant differences were observed in certain behavioural patterns among addicted and non-addicted medical students.

Conclusion:

Internet Addiction (IA) is an emerging mental health concern affecting social behaviour patterns of medical undergraduates. However, the burden of IA is relatively higher among female medical students.

Clinical neuropsychiatric considerations regarding nonsubstance or behavioral addictions

Over the past several decades, non-substance-use behaviors like gambling, gaming, and sex have received greater consideration as possible foci of addictions. In this article, I will review the recent history and current status of non-substance or behavioral addictions. A main focus will involve gambling and gambling disorder, given that the latter is currently the sole non-substance addictive disorder described in the main text of the current (fifth) edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). Internet gaming disorder, currently in the DSM-5 section addressing conditions that may need additional research, will also be considered, as will the concept of Internet addiction. Compulsive sexual behaviors (including problematic pornography use) will be considered, particularly with respect to how behavioral addictions may be considered in the forthcoming 11th edition of the International Classification of Diseases (ICD-11).

Increased Striatal Dopamine Synthesis Capacity in Gambling Addiction

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.

Development and validation of the Canine Reward Responsiveness Scale -Examining individual differences in reward responsiveness of the domestic dog

Although there is ample data indicating that reward processing plays an important role in human psychopathologies and pharmaco- and psychotherapy treatment response, the corresponding animal-model research needs to be extended to models whose motivational and social dispositions are better generalizable than those of the traditional models. Accordingly, our aim was to develop and assess the reliability and validity of an owner-report rating scale of reward responsiveness in domestic dogs (N = 2149) and then to examine individual differences in reward responsiveness. Responsiveness was categorisable by reward type (ball/toy and food) and exhibited individual variability manifesting in age- and breed-related differences. Rating scale scores were associated with behavioural observation of reward processing, indicating evidence of convergent validity. Ball/toy and food reward responsiveness were associated with owner-rated hyperactivity-impulsivity‚ inattention and with differences in training, indicating evidence of concurrent validity. Extreme (vs. average) reward responsiveness was also predicted by dogs’ hyperactivity-impulsivity and inattention‚ and extreme responsiveness was associated with increased likelihood of physical health and/or social problems. These findings are informative with regard to the dog as an animal model for various human behavioural and cognitive functions‚ and also for the dog in its own right as they are relevant to training and welfare.

Decision-Making Under Risk, but Not Under Ambiguity, Predicts Pathological Gambling in Discrete Types of Abstinent Substance Users

This study explored how different forms of reward-based decision-making are associated with pathological gambling (PG) among abstinent individuals with prior dependence on different classes of drugs. Participants had lifetime histories of either "pure" heroin dependence (n = 64), "pure" amphetamine dependence (n = 51), or polysubstance dependence (n = 89), or had no history of substance dependence (n = 133). Decision-making was assessed via two neurocognitive tasks: (1) the Iowa Gambling Task (IGT), a measure of decision-making under ambiguity (i.e., uncertain risk contingencies); and (2) the Cambridge Gambling task (CGT), a measure of decision-making under risk (i.e., explicit risk contingencies). The main effects of neurocognitive performance and drug class on PG (defined as ≥3 DSM-IV PG symptoms) as well as their interactional effects were assessed via multiple linear regression. Two CGT indices of decision-making under risk demonstrated positive main effects on PG. Interaction effects indicated that the effects of decision-making under risk on PG were largely consistent across participant groups. Notably, a linear relationship between greater CGT Risk-Taking and PG symptoms was not observed among amphetamine users, whereas IGT performance was selectively and positively associated with PG in polysubstance users. Overall, results indicate that reward-based decision-making under risk may represent a risk factor for PG across substance users, with some variations in these relationships influenced by specific class of substance of abuse.

P851-Padrões de uso do smartphone potencialmente disfuncionais em adultos portugueses

A globalização da informação em múltiplos domínios da vida dos indivíduos congrega vantagens e riscos. O presente estudo propôs-se avaliar a existência de padrões de uso do smartphone potencialmente disfuncionais junto de uma amostra de conveniência constituída por 164 participantes adultos. Os participantes responderam a: versão portuguesa do Smartphone Addiction Inventory; questionário sociodemográfico; questionário de sintomas clínicos sugestivos de uso problemático/dependência de smartphones. Ainda que a maioria dos participantes (90.9%) não apresente sintomas de perturbação associada ao uso de smartphones, 6.7% apresenta sintomas moderados e 2.4% sintomas graves. Os resultados sugerem a importância da realização de rastreios neste domínio.

Relationship between psychological inflexibility and experiential avoidance and internet addiction: Mediating effects of mental health problems

Internet addiction became a major mental health problem in college student. Our objective was to examine the relationship between psychological inflexibility and experiential avoidance (PIEA) and Internet addiction (IA) and the mediating effects of mental health problem indicators. 500 college students (238 men and 262 women) participated in this study. The level of PIEA was examined using the Acceptance and Action Questionnaire-II. The severity of IA was assessed using the Chen Internet Addiction Scale. The levels of depression, anxiety, interpersonal sensitivity, and hostility were evaluated using the Symptom Checklist-90 item-Revised Scale. The relationship among PIEA, mental health problems, and IA was examined using structural equation modeling. The severity of PIEA was positively associated with the severity of IA as well as positively associated with the severity of mental health problems. In addition, the severity of mental health problem indicators was positively associated with the severity of IA. These results provide the severity of PIEA is directly related to the severity of IA and indirectly related to the severity of IA through increasing the severity of mental health problems. The PIEA should be one of the target objectives when administer cognitive-behavioral therapy to college students with IA and mental health problems.

Impulsivity, implicit attitudes and explicit cognitions, and alcohol dependence as predictors of pathological gambling

Impulsivity, implicit attitudes and explicit cognitions regarding gambling, and alcohol abuse have been pointed out by past research as significant contributors to the development and maintenance of gambling disorders. In this study, we tested the relationship among these contributors and pathological gambling. Forty-four pathological gamblers (DSM-5 criteria), of whom 23 were active gamblers and 17 were alcohol dependent, were compared with 100 controls, consisting of patients with a lifetime history of alcohol use disorder in remission for at least 2 years. The following protocol was used for the comparison: National Opinion Research Center Diagnostic Screen for Gambling Disorders, Barratt Impulsiveness Scale Version 11 (BIS-11), Gambling Related Cognitions Scale (GRCS), Obsessive Compulsive Drinking Scale, Alcohol Use Disorders Identification Test, and Gambling Implicit Association Test (IAT). Impulsivity (BIS-11) and changes in implicit attitudes (IAT) were able to discriminate between pathological gamblers and controls, the latter being less impulsive and having fewer implicit attitudes towards gambling. Cognitive impulsivity (BIS-11), explicit gambling cognitions (GRCS), and alcohol dependence were able to discriminate between active and non-active pathological gamblers, the latter having less cognitive impulsivity and less explicit gambling cognitions and alcohol dependence. Using these simple tools can help clinicians in the assessment of pathological gambling.

Internet Addiction and Relationships with Insomnia, Anxiety, Depression, Stress and Self-Esteem in University Students: A Cross-Sectional Designed Study

BACKGROUND AND AIMS

Internet addiction (IA) could be a major concern in university medical students aiming to develop into health professionals. The implications of this addiction as well as its association with sleep, mood disorders and self-esteem can hinder their studies, impact their long-term career goals and have wide and detrimental consequences for society as a whole. The objectives of this study were to: 1) Assess potential IA in university medical students, as well as factors associated with it; 2) Assess the relationships between potential IA, insomnia, depression, anxiety, stress and self-esteem.

METHODS

Our study was a cross-sectional questionnaire-based survey conducted among 600 students of three faculties: medicine, dentistry and pharmacy at Saint-Joseph University. Four validated and reliable questionnaires were used: the Young Internet Addiction Test, the Insomnia Severity Index, the Depression Anxiety Stress Scales (DASS 21), and the Rosenberg Self Esteem Scale (RSES).

RESULTS

The average YIAT score was 30 ± 18.474; Potential IA prevalence rate was 16.8% (95% confidence interval: 13.81-19.79%) and it was significantly different between males and females (p-value = 0.003), with a higher prevalence in males (23.6% versus 13.9%). Significant correlations were found between potential IA and insomnia, stress, anxiety, depression and self-esteem (p-value < 0.001); ISI and DASS sub-scores were higher and self-esteem lower in students with potential IA.

CONCLUSIONS

Identifying students with potential IA is important because this addiction often coexists with other psychological problems. Therefore, interventions should include not only IA management but also associated psychosocial stressors such as insomnia, anxiety, depression, stress, and self-esteem.

Predictors and patterns of problematic Internet game use using a decision tree model

Background and aims Problematic Internet game use is an important social issue that increases social expenditures for both individuals and nations. This study identified predictors and patterns of problematic Internet game use. Methods Data were collected from online surveys between November 26 and December 26, 2014. We identified 3,881 Internet game users from a total of 5,003 respondents. A total of 511 participants were assigned to the problematic Internet game user group according to the Diagnostic and Statistical Manual of Mental Disorders Internet gaming disorder criteria. From the remaining 3,370 participants, we used propensity score matching to develop a normal comparison group of 511 participants. In all, 1,022 participants were analyzed using the chi-square automatic interaction detector (CHAID) algorithm. Results According to the CHAID algorithm, six important predictors were found: gaming costs (50%), average weekday gaming time (23%), offline Internet gaming community meeting attendance (13%), average weekend and holiday gaming time (7%), marital status (4%), and self-perceptions of addiction to Internet game use (3%). In addition, three patterns out of six classification rules were explored: cost-consuming, socializing, and solitary gamers. Conclusion This study provides direction for future work on the screening of problematic Internet game use in adults.

Are Mental Health Effects of Internet Use Attributable to the Web-Based Content or Perceived Consequences of Usage? A Longitudinal Study of European Adolescents

BACKGROUND

Adolescents and young adults are among the most frequent Internet users, and accumulating evidence suggests that their Internet behaviors might affect their mental health. Internet use may impact mental health because certain Web-based content could be distressing. It is also possible that excessive use, regardless of content, produces negative consequences, such as neglect of protective offline activities.

OBJECTIVE

The objective of this study was to assess how mental health is associated with (1) the time spent on the Internet, (2) the time spent on different Web-based activities (social media use, gaming, gambling, pornography use, school work, newsreading, and targeted information searches), and (3) the perceived consequences of engaging in those activities.

METHODS

A random sample of 2286 adolescents was recruited from state schools in Estonia, Hungary, Italy, Lithuania, Spain, Sweden, and the United Kingdom. Questionnaire data comprising Internet behaviors and mental health variables were collected and analyzed cross-sectionally and were followed up after 4 months.

RESULTS

Cross-sectionally, both the time spent on the Internet and the relative time spent on various activities predicted mental health (P<.001), explaining 1.4% and 2.8% variance, respectively. However, the consequences of engaging in those activities were more important predictors, explaining 11.1% variance. Only Web-based gaming, gambling, and targeted searches had mental health effects that were not fully accounted for by perceived consequences. The longitudinal analyses showed that sleep loss due to Internet use (ß=.12, 95% CI=0.05-0.19, P=.001) and withdrawal (negative mood) when Internet could not be accessed (ß=.09, 95% CI=0.03-0.16, P<.01) were the only consequences that had a direct effect on mental health in the long term. Perceived positive consequences of Internet use did not seem to be associated with mental health at all.

CONCLUSIONS

The magnitude of Internet use is negatively associated with mental health in general, but specific Web-based activities differ in how consistently, how much, and in what direction they affect mental health. Consequences of Internet use (especially sleep loss and withdrawal when Internet cannot be accessed) seem to predict mental health outcomes to a greater extent than the specific activities themselves. Interventions aimed at reducing the negative mental health effects of Internet use could target its negative consequences instead of the Internet use itself.

TRIAL REGISTRATION

International Standard Randomized Controlled Trial Number (ISRCTN): 65120704; http://www.isrctn.com/ISRCTN65120704?q=&filters=recruitmentCountry:Lithuania&sort=&offset= 5&totalResults=32&page=1&pageSize=10&searchType=basic-search (Archived by WebCite at http://www.webcitation/abcdefg).

Internet Addiction and Other Behavioral Addictions

The Internet is increasingly influential in the lives of adolescents. Although there are many positives, there are also risks related to excessive use and addiction. It is important to recognize clinical signs and symptoms of Internet addiction (compulsive use, withdrawal, tolerance, and adverse consequences), treat comorbid conditions (other substance use disorders, attention deficit hyperactivity disorder, anxiety, depression, and hostility), and initiate psychosocial interventions. More research on this topic will help to provide consensus on diagnostic criteria and further clarify optimal management.

Gambling Disorder Due to Brazilian Animal Game ("Jogo do bicho"): Gambling Behavior and Psychopathology

Gambling is currently widespread across the globe and despite legally restricted, it is significantly common in Brazil. A traditional and common form of gambling in Brazil is the Brazilian animal game (BAG)--"Jogo do bicho" in Portuguese. In 2013, BAG activities collected approximately 19 billion Brazilian reais--equivalent to more than 8 billon American dollars, a figure almost 60 % higher than legal lotteries. Although a common form of gambling, the gambling behavior and psychopathology of gambling disorder (GD) associated with BAG has never been systematically studied. The aim of this study is to conduct, the first research approaching GD due to BAG. We assessed 897 participants of whom 63 subjects (7.0 %) presented with GD due to BAG and 834 with GD associated with other forms of gambling. After comparing these two groups, major differences were found in demographics, gambling behavior elements and psychopathological variables. This research reinforces the need for further research on BAG and the need for specific approaches in GD. The particularities of BAG may affect treatment strategies as, for example, suggest some adaptations in social and psychotherapeutic approaches. We also highlight the need to acknowledge the "hidden" BAG as a potential addictive game.

Heritability of compulsive Internet use in adolescents

Over the past decades, Internet use has grown substantially, and it now serves people as a supportive tool that is used regularly and—in large parts of the world—inevitably. Some people develop problematic Internet use, which may lead to addictive behavior and it is becoming important to explore the risk factors for compulsive Internet use. Data were analyzed on compulsive Internet use [with the Compulsive Internet Use Scale (CIUS)] from 5247 monozygotic (MZ) and dizygotic (DZ) adolescent twins registered with the Netherlands Twin Register. The participants form a sample that is informative for genetic analyses, allowing the investigation of the causes of individual differences in compulsive Internet use. The internal consistency of the instrument was high and the 1.6‐year test–retest correlation in a subsample (n = 902) was 0.55. CIUS scores increased slightly with age. Remarkably, gender did not explain variation in CIUS scores, as mean scores on the CIUS were the same in boys and girls. However, the time spent on specific Internet activities differed: boys spent more time on gaming, whereas girls spent more time on social network sites and chatting. The heritability estimates were the same for boys and girls: 48 percent of the individual differences in CIUS score were influenced by genetic factors. The remaining variance (52 percent) was due to environmental influences that were not shared between family members. Because a life without Internet is almost impossible nowadays, it is important to further explore the determinants of compulsive Internet use, including genetic risk factors.

Brain Activity During Cocaine Craving and Gambling Urges: An fMRI Study

Although craving states are important to both cocaine dependence (CD) and pathological gambling (PG), few studies have directly investigated neurobiological similarities and differences in craving between these disorders. We used functional magnetic resonance imaging (fMRI) to assess brain activity in 103 participants (30 CD, 28 PG, and 45 controls) while they watched videos depicting cocaine, gambling, and sad scenarios to investigate the neural correlates of craving. We observed a three-way urge type × video type × diagnostic group interaction in self-reported craving, with CD participants reporting strong cocaine cravings to cocaine videos, and PG participants reporting strong gambling urges to gambling videos. Neuroimaging data revealed a diagnostic group × video interaction in anterior cingulate cortex/ventromedial prefrontal cortex (mPFC), activating predominantly to cocaine videos in CD participants, and a more dorsal mPFC region that was most strongly activated for cocaine videos in CD participants, gambling videos in PG participants, and sad videos in control participants. Gender × diagnosis × video interactions identified dorsal mPFC and a region in posterior insula/caudate in which female but not male PG participants showed increased responses to gambling videos. Findings illustrate both similarities and differences in the neural correlates of drug cravings and gambling urges in CD and PG. Future studies should investigate diagnostic- and gender-specific therapies targeting the neural systems implicated in craving/urge states in addictions.

Recorded Behavior as a Valuable Resource for Diagnostics in Mobile Phone Addiction: Evidence from Psychoinformatics

Psychologists and psychiatrists commonly rely on self-reports or interviews to diagnose or treat behavioral addictions. The present study introduces a novel source of data: recordings of the actual problem behavior under investigation. A total of N = 58 participants were asked to fill in a questionnaire measuring problematic mobile phone behavior featuring several questions on weekly phone usage. After filling in the questionnaire, all participants received an application to be installed on their smartphones, which recorded their phone usage for five weeks. The analyses revealed that weekly phone usage in hours was overestimated; in contrast, numbers of call and text message related variables were underestimated. Importantly, several associations between actual usage and being addicted to mobile phones could be derived exclusively from the recorded behavior, but not from self-report variables. The study demonstrates the potential benefit to include methods of psychoinformatics in the diagnosis and treatment of problematic mobile phone use.

Association of stress coping strategies with Internet addiction in college students: The moderating effect of depression

BACKGROUND

This study examined the association between stress-related coping strategies and Internet addiction and the moderating effect of depression in a sample of Taiwanese college students.

METHOD

A total of 500 college students (238 men and 262 women) participated in this study. Internet addiction was assessed using the Chen Internet Addiction Scale. Participants' stress coping strategies and depressive symptoms were measured using the Coping Orientation to Problems Experienced and the Beck Depression Inventory-II, respectively. We used t and chi-square tests to examine differences in demographic characteristics, depression, and stress coping strategies between participants with and without Internet addiction. Significant variables were used in a logistic regression model to examine the association between stress coping strategies and Internet addiction and the moderating effect of depression on the association.

RESULTS

Results indicated that use of restraint coping was negatively associated with Internet addiction (odds ratio [OR]=0.886, 95% confidence interval [CI]: 0.802-0.977), whereas denial (OR=1.177, 95% CI: 1.029-1.346) and mental disengagement (OR=2.673, 95% CI: 1.499-4.767) were positively associated with Internet addiction. Depression had a moderating effect on the association between denial and Internet addiction (OR=0.701, 95% CI: 0.530-0.927).

CONCLUSIONS

Stress coping strategies and depression are important factors to evaluate when developing intervention programs targeting college undergraduate students with Internet addiction.

Italian Adolescent Gambling Behaviour: Psychometric Evaluation of the South Oaks Gambling Screen: Revised for Adolescents (SOGS-RA) among a sample of Italian students

Since no Italian validated instrument focuses specifically on the measurement of pathological gambling in very young people, with this study, we aim to adapt an international instrument (SOGS-RA) and assess its psychometric properties in a sample (n = 14.910) of young Italian students aged between 15 and 19 years. Cross-cultural adaptation of the instrument was performed through translation, synthesis of translation, back-translation, expert committee review, and pre-testing. The kappa statistic for test-retest concordance ranged from 0.53 to 0.80. Internal validity was assessed by the MCA that identified one principal component with eigenvalue equal to 3,875: the Divgi index and very simple structure analysis also pointed out one common factor, so uni-dimensionality of the SOGS-RA was accepted. Moreover the SOGS-RA was found to have acceptable internal consistency (α = 0.780). Cronbach's alpha was also assessed separately among males and females (respectively 0.786 and 0.707). The SOGS-RA was assessed in relation to gambling frequency, alcohol and drug use: Chi squared test revealed a strong association both for males and females with gambling frequency (p value ≤ 0.0001), frequent use of illicit drugs (for each drug p value ≤ 0.0001) and having had 3 or more occasions of binge drinking in the last month (p value ≤ 0.0001). At the end we can say that, the results of our study suggest that the SOGS-RA screen may be useful to assess at-risk or problem gambling for both genders in comprehensive youth surveys.

Internet gaming disorder, social network disorder and laterality: handedness relates to pathological use of social networks

The internet age bears new challenges that include health risks. It is agreed that excessive internet use may reach pathological levels. However, the concept of internet addiction lacks specificity and, therefore, warrants studies on its diagnostic and etiologic classification. This study was conducted to characterize the novel DSM-5 criteria for internet gaming disorder and the adapted criteria for the “social network disorder”. Based on the established association of handedness and substance use disorders, we also explored whether internet use related to laterality. For this study, 3,287 volunteers participated in the online survey and gave particulars concerning their internet use in general, internet gaming and use of social networks, laterality markers (hand, foot, eye, ear, rotational preference in gymnastics, and head turning asymmetry) and health status. Of the participants, 1.1 % fulfilled the criteria for internet gaming disorder, and 1.8 % fulfilled the criteria for social network disorder. The applied criteria were highly correlated with the time spent on the respective internet activities (p < 4 × 10⁻⁵⁶). The analyses of comorbidity and working hours support the thresholds of 5/9 criteria and ≥30 h/week spent on the internet for the classification as pathological (p < 5 × 10⁻²). Moreover, we found that left-handedness related to more affirmed criteria and longer times spent on social networks (p ≤ 4 × 10⁻²). The provided criteria proved to be user-friendly, comprehensible and well accepted. The results contribute to a better understanding of pathological internet gaming and social network use and provide evidence that biological markers of substance use disorders are involved in internet addiction.

Altered reward processing in pathological computer gamers--ERP-results from a semi-natural gaming-design

INTRODUCTION

Internet Gaming Disorder has been added as a research diagnosis in section III for the DSM-V. Previous findings from neuroscientific research indicate an enhanced motivational attention toward cues related to computer games, similar to findings in substance-related addictions. On the other hand in clinical observational studies tolerance effects are reported by patients with Internet Gaming disorder. In the present study we investigated whether an enhanced motivational attention or tolerance effects are present in patients with Internet Gaming Disorder.

METHODS

A clinical sample from the Outpatient Clinic for Behavioral Addictions in Mainz, Germany was recruited, fulfilling the diagnostic criteria for Internet Gaming Disorder. In a semi-natural EEG design participants played a computer game during the recording of event-related potentials to assess reward processing.

RESULTS

The results indicated an attenuated P300 for patients with Internet Gaming Disorder in response to rewards in comparison to healthy controls, while the latency of N100 was prolonged and the amplitude of N100 was increased.

CONCLUSIONS

Our findings support the hypothesis that tolerance effects are present in patients with Internet Gaming Disorder, when actively playing computer games. In addition, the initial orienting toward the gaming reward is suggested to consume more capacity for patients with Internet Gaming Disorder, which has been similarly reported by other studies with other methodological background in disorders of substance-related addictions.

Gambling disorder and other behavioral addictions: recognition and treatment

Addiction professionals and the public are recognizing that certain nonsubstance behaviors--such as gambling, Internet use, video-game playing, sex, eating, and shopping--bear resemblance to alcohol and drug dependence. Growing evidence suggests that these behaviors warrant consideration as nonsubstance or "behavioral" addictions and has led to the newly introduced diagnostic category "Substance-Related and Addictive Disorders" in DSM-5. At present, only gambling disorder has been placed in this category, with insufficient data for other proposed behavioral addictions to justify their inclusion. This review summarizes recent advances in our understanding of behavioral addictions, describes treatment considerations, and addresses future directions. Current evidence points to overlaps between behavioral and substance-related addictions in phenomenology, epidemiology, comorbidity, neurobiological mechanisms, genetic contributions, responses to treatments, and prevention efforts. Differences also exist. Recognizing behavioral addictions and developing appropriate diagnostic criteria are important in order to increase awareness of these disorders and to further prevention and treatment strategies.

The addiction-related gene ANKK1 in Parkinsonian patients with impulse control disorder

Impulse control disorders (ICDs) comprise a wide spectrum of abnormal behaviors frequently found in patients with Parkinson's disease (PD) receiving antiparkinsonian treatment. Some ICDs share several essential features with substance use disorders. In this work, we have studied the addiction-related gene ankyrin repeat and kinase domain containing I (ANKK1) in a sample of PD patients involved in a multicenter study on ICD. We carried out the TaqIA ANKK1 single-nucleotide polymorphism (SNP) genotyping in PD patients. Clinical assessment of ICD was performed using the Questionnaire for impulsive-compulsive disorders in PD. We found no association between TaqIA SNP and ICD in PD patients (p = 0.565). However, when PD patients were grouped according the diagnosis of any ICD with a potentially addictive reinforcement (ICDARs), A1- TaqIA genotype showed significant association (p = 0.036). No association was found for the presence of punding in PD patients (p = 0.289). A logistic regression analysis confirmed the independent effect of the A1- genotype upon ICDARs (OR 8.76, 95 % CI 1.3-57.8, Wald = 5.805, p = 0.024). The TaqIA genotype A1- is associated to ICDAR in our sample and it may differentiate two types of disorders which are part of the ICD definition in PD patients.

Contribution of illegal acts to pathological gambling diagnosis: DSM-5 implications

The purposes of this study were to examine the specific contribution of illegal acts to the diagnostic criteria of pathological gambling, to assess the possibility of differential item functioning across patients' sex and age, and to explore the existence of different clinical phenotypes based on the presence of illegal acts. The sample consisted of 2,155 patients seeking treatment for pathological gambling at the University Hospital of Bellvitge in Barcelona, Spain. The illegal acts item did not show different item functioning, and younger patients presented higher latent means than middle-aged and older patients, whereas no differences were found across sex. This item also showed the lowest discrimination coefficient; its exclusion would maintain satisfactory internal consistency for the remaining 9 symptoms and was poorly related to psychopathology and the severity of the gambling behavior. The relevance of the illegal acts as a diagnostic criterion appears to be limited, and its elimination from the Diagnostic and Statistical Manual for Mental Disorders, 5th edition, seems justified. However, illegal acts have implications for both the clinical and legal domains and contribute to increase the patients' impairment.

In vivo evidence for greater amphetamine-induced dopamine release in pathological gambling: a positron emission tomography study with [(11)C]-(+)-PHNO

Drug addiction has been associated with deficits in mesostriatal dopamine (DA) function, but whether this state extends to behavioral addictions such as pathological gambling (PG) is unclear. Here we used positron emission tomography and the D3 receptor-preferring radioligand [(11)C]-(+)-PHNO during a dual-scan protocol to investigate DA release in response to oral amphetamine in pathological gamblers (n=12) and healthy controls (n=11). In contrast with human neuroimaging findings in drug addiction, we report the first evidence that PG is associated with greater DA release in dorsal striatum (54-63% greater [(11)C]-(+)-PHNO displacement) than controls. Importantly, dopaminergic response to amphetamine in gamblers was positively predicted by D3 receptor levels (measured in substantia nigra), and related to gambling severity, allowing for construction of a mechanistic model that could help explain DA contributions to PG. Our results are consistent with a hyperdopaminergic state in PG, and support the hypothesis that dopaminergic sensitization involving D3-related mechanisms might contribute to the pathophysiology of behavioral addictions.