Heritability of compulsive Internet use in adolescents

Gene-environment interaction between gaming addiction and perceived stress in late adolescents and young adults: A twin study

Background and aims

The association between perceived stress (PS) and gaming addiction (GA) is well documented. However, the mechanism for explaining this association remains unclear. Using a genetically informative design, this study aims to distinguish between the diathesis-stress and bio-ecological models of gene by environment interaction (G x E) to explain the underlying mechanism of the relationship.

Methods

In total, 1,468 twins (mean age = 22.6 ± 2.8 years) completed an online survey including the GA and PS scales. Twin correlations for GA and PS were computed and univariate model-fitting analysis was conducted to determine genetic and environmental influences on GA and PS. The bivariate G x E model-fitting analysis was performed to determine the best G x E interaction model.

Results

Additive genetic, shared environmental, and non-shared environmental effects were 0.70 (95%CI = 0.61, 0.77), 0.00, and 0.30 (95%CI = 0.26, 0.33), and 0.38 (95%CI = 0.24, 0.55), 0.35 (95% CI = 0.18, 0.51), and 0.22 (95%CI = 0.20, 0.26) for GA and PS, respectively. Bivariate G x E model-fitting analysis supported the diathesis-stress model, where genetic influences on GA were greater in higher levels of PS, whereas environmental influences on GA were small and constant across levels of PS.

Discussion and conclusions

The evidence for the diathesis-stress model for GA is consistent with the etiological process of many forms of psychopathology. The findings should be incorporated in clinical settings to improve the treatment of GA, and used in developments of intervention and prevention methods for GA.

Genetic Aspects of Problematic and Risky Internet Use in Young Men-Analysis of ANKK1, DRD2 and NTRK3 Gene Polymorphism

BACKGROUND

Internet addiction disorder (IAD) is characterized by an excess of uncontrolled preoccupations, urges, or behaviors related to computer use and Internet access that culminate in negative outcomes or individual distress. PIU includes excessive online activities (such as video gaming, social media use, streaming, pornography viewing, and shopping). The aim of this study was to analyze the association of gene polymorphisms that may influence the severity of risky behaviors in young men with the frequency of Internet use. We speculate that there are individual differences in the mechanisms of Internet addiction and that gene-hormone associations may represent useful biomarkers for subgroups of individuals.

MATERIALS AND METHODS

The study was conducted in a sample of 407 adult males. Subjects were asked to complete the Problematic Internet Use Test (PIUT). Serum was analyzed to determine concentrations of luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone (TT), sex hormone binding protein (SHBG), dehydroepiandrosterone sulfate (DHEA-S), estradiol (E2), prolactin (PRL), insulin (I), serotonin (5-HT), and dopamine (DA), as well as DRD2, ANKK1, and NTRK3 gene polymorphisms.

RESULTS

In the analysis of the ANKK1 gene, there was a specific association between ANKK1 polymorphisms and PRL and 5-HT blood concentrations. There was also an association between the ANKK1 polymorphisms and LH and DA concentrations. When analyzing the DRD2 gene polymorphism, we found that in the group with a moderate level of Internet dependence, there was an association between both the G/GG and GG/GG polymorphisms and FSH concentration.

CONCLUSIONS

Our study found that there may be an association between the NTRK3 gene polymorphism and PIU. The polymorphisms of ANKK1 and DRD2 genes may be factors that influence the concentrations of hormones (PRL, 5-HT, DA) that are associated with the results obtained in PIU.

The genetics of gaming: A longitudinal twin study

Background

Gaming is a popular past-time activity among children and adolescents, but it there is also a possible link to negative consequences such as psychological distress and lowered academic achievement. However, there are fundamental knowledge gaps remaining regarding central characteristics of gaming such as heritability, stability over time, and sex differences. We examined the genetic and environmental contribution to gaming behavior, including sex differences, continuity and change, in a longitudinal cohort of twins.

Methods

This is the first longitudinal twin study on gaming, involving 32,006 twins in Sweden. Parents were asked about the twins' gaming at ages 9, 15 and 18. We used univariate and multivariate twin analyses to estimate the relative contribution of genetic and environmental influences at each time-point as well as across time. Sex-differences were also explored.

Results

The results showed large sex differences, where genetics explained more of the variance for boys (31.3%-62.5% depending on age) than for girls (19.4%-23.4%). Genetic factors explained an increasing amount of the variance for boys (31.3% at age 9, 62.5% at age 15 and 53.9% at age 18). Shared environmental factors explained a larger proportion of the variance among girls, which remained relatively stable over time (70.5% at age 9, 61.8% at age 15 and 60.5% at age 18). The results also indicated that most of the variance came from genetic and environmental sources specific to each age.

Conclusions

Compared to many other behavioral phenotypes, such as gambling, gaming was relatively unstable with a large degree of genetic innovation. There were large sex differences in the contribution of genetic and environmental factors. This suggests that excessive gaming could be the result of age- and sex-specific genetic and environmental factors, and should be taken into account when mapping gaming behaviors, since these behaviors might be under continual etiological transformation.

Problematic Internet Use in adolescents: New psychometric evidence for the Spanish short form of the Compulsive Internet Use Scale

OBJECTIVES

Problematic Internet Use (PIU) has become a worldwide problem in recent years. Among screening instruments for PIU, the Compulsive Internet Use Scale (CIUS) is perhaps the most widely used. Psychometric properties of the full CIUS are not convincing, however, and the short form (CIUS-S) has shown promising results, albeit limited to the English version, with little evidence in Spanish. Therefore, the aim of the present work was to study the psychometric properties of the CIUS-S scores in a large sample of Spanish adolescents.

METHOD

The sample consisted of 1790 participants, 816 male (45.6%), 961 female (53.7%), and 13 other (0.7%) . Mean age was 15.70 years (SD = 1.26).

RESULTS

The five-items one-dimensional model displayed appropriate goodness-of-fit indices. Strong measurement invariance model across age and partial across gender was found. Furthermore, the CIUS-S was positively associated with several indicators of poor well-being and mental health, and negatively associated with prosocial behavior, self-esteem, and feeling of belonging.

CONCLUSION

Overall, the CIUS-S scores appear reliable and valid in its Spanish version for adolescent populations, supporting its aim to detect and prevent a problem that has become a major worldwide issue in the last years.

Neurobiological risk factors for problematic social media use as a specific form of Internet addiction: A narrative review

Problematic social media use (PSMU) is a behavioral addiction, a specific form of problematic Internet use associated with the uncontrolled use of social networks. It is typical mostly for modern adolescents and young adults, which are the first generations fully grown up in the era of total digitalization of society. The modern biopsychosocial model of the formation of behavioral addictions, postulating the impact of a large number of biological, psychological, and social factors on addictive behavior formation, may be quite applicable to PSMU. In this narrative review, we discussed neurobiological risk factors for Internet addiction with a focus on current evidence on the association between PSMU and structural/ functional characteristics of the brain and autonomic nervous system, neurochemical correlations, and genetic features. A review of the literature shows that the vast majority of the mentioned neurobiological studies were focused on computer games addiction and generalized Internet addiction (without taking into account the consumed content). Even though a certain number of neuroimaging studies have been conducted for PSMU, there is practically no research on neuropeptide and genetic associations for PSMU to date. This fact points to the extremely high relevance of such studies.

The first genome-wide association study of internet addiction; Revealed substantial shared risk factors with neurodevelopmental psychiatric disorders

BACKGROUND

Internet addiction disorder (IAD) is listed as a disorder requiring further studies in the diagnostic and statistical manual of mental disorders (DSM-V). Psychological studies showed significant co-morbidity of IAD with depression, alcohol abuse, and anxiety disorder. Etiology and genetic bases of IAD are unclear.

AIMS

Present study aimed to investigate the genetic, psychological, and cognitive bases of a tendency to internet addiction.

METHODS AND PROCEDURES

DNA was extracted from blood samples of IADs (N = 16,520) and 18,000 matched non-psychiatric subjects. Genotyping for the subjects was performed using SNP Array. Psychological, neuropsychological, and neurological characteristics were conducted.

OUTCOMES AND RESULTS

Seventy-two SNPs in 24 genes have been detected significantly associated with IAD. Most of these SNPs were risk factors for psychiatric disorders. Most similarity detected with autism spectrum disorder, bipolar disorder and schizophrenia. Higher anxiety, stress, and neuroticism and deficits in working memory, attention, planning, and processing speed were detected in IADs.

CONCLUSIONS

This study is the first genome-wide association study of IAD that showed strong shared genetic bases with neurodevelopmental disabilities and psychiatric disorders.

IMPLICATIONS

Genetic risk factors in IADs may cause several cognitive and neurodevelopmental brain function abnormalities, which lead to excessive Internet usage. It may suggest that IAD could be a marker for vulnerability to developmental psychiatric disorders.

Gene-environment correlations and genetic confounding underlying the association between media use and mental health

The increase in online media use and mental health problems have prompted investigations into their association, although most literature is focussed on deleterious effects. We assessed the aetiology of media use and mental health associations (M age = 22.14, SD = 0.85) using twin (n = 4000 pairs) and polygenic score methods (n = 6000 unrelated individuals) in the Twins Early Development Study. Beyond the traditionally explored negative uses of online media (online victimisation and problematic internet use), we investigate general media uses such as posting online and watching videos and distinguish both positive (pro-social behaviour) and negative (anxiety, depression, peer and behaviour problems) mental health measures. Negative media use correlated with poor mental health (r = 0.11-0.32), but general media use correlated with prosocial behaviour (r = 0.20) and fewer behavioural problems (r =  - 0.24). Twin analyses showed that both general and negative media use were moderately heritable (ranging from 20 to 49%) and their associations with mental health were primarily due to genetic influences (44-88%). Genetic sensitivity analysis combining polygenic scores with heritability estimates also suggest genetic confounding. Results indicate research on the mental health impact of media use should adopt genetically informed designs to strengthen causal inference.

Problematic Internet Use among Adolescents 18 Months after the Onset of the COVID-19 Pandemic

Studies in recent years and especially since the beginning of the COVID-19 pandemic have shown a significant increase in the problematic use of computer games and social media. Adolescents having difficulties in regulating their unpleasant emotions are especially prone to Problematic Internet Use (PIU), which is why emotion dysregulation has been considered a risk factor for PIU. The aim of the present study was to assess problematic internet use (PIU) in adolescents after the third wave (nearly 1.5 years after the onset in Europe) of the COVID-19 pandemic. In the German region of Siegen-Wittgenstein, all students 12 years and older from secondary-level schools, vocational schools and universities were offered a prioritized vaccination in August 2021 with an approved vaccine against COVID-19. In this context, the participants filled out the Short Compulsive Internet Use Scale (SCIUS) and two additional items to capture a possible change in digital media usage time and regulation of negative affect due to the COVID-19 pandemic. A multiple regression analysis was performed to identify predictors of PIU. The original sample consisted of 1477 participants, and after excluding invalid cases the final sample size amounted to 1268 adolescents aged 12-17 (x = 14.37 years, SD = 1.64). The average prevalence of PIU was 43.69%. Gender, age, digital media usage time and the intensity of negative emotions during the COVID-19 pandemic were all found to be significant predictors of PIU: female gender, increasing age, longer digital media usage time and higher intensity of negative emotions during the COVID-19 pandemic were associated with higher SCIUS total scores. This study found a very high prevalence of PIU among 12- to 17-year-olds for the period after the third wave of the COVID-19 pandemic, which has increased significantly compared to pre-pandemic prevalence rates. PIU is emerging as a serious problem among young people in the pandemic. Besides gender and age, pandemic-associated time of digital media use and emotion regulation have an impact on PIU, which provides starting points for preventive interventions.

Characteristics of online behavior and structure of consumed content in Abakan adolescents of different age, groups and ethnicity

Background. The study of the prevalence and structure of various types of online behavior, the characteristics of the content consumed by adolescents of different age, sex and ethnic groups is an important area of scientific research.

The aim. To study the features of online behavior and the structure of content consumed in Abakan adolescents of various age and sex groups and ethnicity (Russians and Khakasses).

Materials and methods. 1400 adolescents of the city of Abakan (Republic of Khakassia) aged 12–18 were examined: 962 (68.7 %) Russians, 438  (31.3  %) Khakasses, 678 (48.4 %) boys and 722 (51.6 %) girls, aged 12–14 years – 39.8 % and 15–18 years – 60.2 %. The type of online behavior was verified using the Chen scale (CIAS). Emotional and behavioral disorders were diagnosed using the SDQ questionnaire. The indicators were compared in groups formed by sex, age and ethnicity. The data were processed using the Statistica 12.0 program (StatSoft Inc., USA).

Results. It has been established that the prevalence and structure of online behavior among adolescents in Abakan depends on gender, age and ethnicity. Pathological Internet use (PIU) is more common among Khakasses, more often in the older age group. Regardless of ethnicity, maladaptive online behavior (pathological and maladaptive Internet use) is recorded more often among girls. In the structure of consumed content, gaming addiction prevails, social network addiction is in second place, and the proportion of mixed and undifferentiated Internet addiction is less. Dependence on online games prevails in boys, while dependence on social networks and undifferentiated internet addiction prevail in girls.

Conclusion. One of the reasons for the greater prevalence of maladaptive online behavior among Khakasses may be the association of maladaptive Internet use with the presence of emotional disorders and behavioral problems that reach the borderline level and are causally significant factors in the development of Internet addiction. Adolescents with maladaptive online behavior, who have not yet reached the level of formed Internet addiction, are the target group requiring medical and psychological assistance.

A bidirectional association between internet addiction and depression: A large-sample longitudinal study among Chinese university students

BACKGROUND

Internet addiction (IA) is associated with adverse consequences, especially for younger people. Evidence indicates that IA is associated with depression, but no studies have yet investigated potential common vulnerability between them.

METHODS

IA (measured by the Young's 20-item Internet Addiction Test Scale) and depressive symptoms (measured by the Patient Health Questionnaire-9 Scale) among 12 043 undergraduates were surveyed at baseline and at a respective 12 month follow-up for each participant. Application of a cross-lagged panel model approach (CLPM) revealed an association between IA and depression after adjusting for demographic variables.

RESULTS

Rates of baseline IA and depression were 5.47% (95% CI: 5.07%, 5.88%) and 3.85% (95% CI: 3.51%, 4.20%), respectively; increasing to 9.47% (95% CI: 8.94%, 9.99%) and 5.58% (95% CI: 5.17%,5.99%), respectively, at follow-up. Rates of new-incidences of IA and depression over 12 months were 7.43% (95% CI: 6.95%, 7.91%) and 4.47% (95% CI: 4.09%, 4.84%), respectively. Models in the present analysis revealed that baseline depression had a significant net-predictive effect on follow-up IA, and baseline IA had a significant net-predictive effect on follow-up depression.

LIMITATIONS

The follow-up survey response rate was moderate (54.69%) in this analysis of university students. Moreover, the IAT-20 scale did not allow differentiate between specific forms of Internet activity.

CONCLUSIONS

Common vulnerability and bidirectional cross-causal effects may both contribute to the association between IA and depression, with common vulnerability likely playing a more significant role than cross-causal effects.

GABRB2, a key player in neuropsychiatric disorders and beyond

The GABA receptors represent the main inhibitory system in the central nervous system that ensure synaptogenesis, neurogenesis, and the regulation of neuronal plasticity and learning. GABAA receptors are pentameric in structure and belong to the Cys-loop superfamily. The GABRB2 gene, located on chromosome 5q34, encodes the β2 subunit that combines with the α and γ subunits to form the major subtype of GABAA receptors, which account for 43% of all GABAA receptors in the mammalian brain. Each subunit probably consists of an extracellular N-terminal domain, four membrane-spanning segments, a large intracellular loop between TM3 and TM4, and an extracellular C-terminal domain. Alternative splicing of the RNA transcript of the GABRB2 gene gives rise at least to four long and short isoforms with dissimilar electrophysiological properties. Furthermore, GABRB2 is imprinted and subjected to epigenetic regulation and positive selection. It has been associated with schizophrenia first in Han Chinese, and subsequently validated in other populations. Gabrb2 knockout mice also exhibited schizophrenia-like behavior and neuroinflammation that were ameliorated by the antipsychotic drug risperidone. GABRB2 was also associated with other neuropsychiatric disorders including bipolar disorder, epilepsy, autism spectrum disorder, Alzheimer's disease, frontotemporal dementia, substance dependence, depression, internet gaming disorder, and premenstrual dysphoric disorder. Recently, it has been postulated that GABRB2 might be a potential marker for different cancer types. As GABRB2 has a pivotal role in the central nervous system and is increasingly recognized to contribute to human diseases, further understanding of its structure and function may expedite the generation of new therapeutic approaches.

Global prevalence of gaming disorder: A systematic review and meta-analysis

BACKGROUND

Gaming disorder was included in the latest revision of the International Classification of Diseases (11th ed.). Worldwide, prevalence estimates of gaming disorder are considerably heterogeneous and often appear to be exceedingly high. However, few studies have examined the methodological, cultural and/or demographic factors that might explain this phenomenon. This review employed meta-analytic techniques to compute the worldwide-pooled prevalence of gaming disorder and evaluate the potential contributing factors for varied prevalence estimates.

METHOD

Prevalence estimates were extracted from 53 studies conducted between 2009 and 2019, which included 226,247 participants across 17 different countries. Study findings were meta-analyzed using a random-effects model. Subgroup and moderator analyses examined potential sources of heterogeneity, including assessment tool and cut-off, participant age and gender, sample size and type, study region, and year of data collection.

RESULTS

The worldwide prevalence of gaming disorder was 3.05% (confidence interval: [2.38, 3.91]); this figure was adjusted to 1.96% [0.19, 17.12] when considering only studies that met more stringent sampling criteria (e.g. stratified random sampling). However, these estimates were associated with significant variability. The choice of screening tool accounted for 77% of the variance, with the Lemmens Internet gaming disorder-9, Gaming Addiction Identification Test and Problematic Videogame Playing scales associated with the highest estimates. Adolescent samples, lower cut-off scores and smaller sample size were significant predictors of higher prevalence. Gaming disorder rates were approximately 2.5:1 in favor of males compared to females.

CONCLUSION

The worldwide prevalence of gaming disorder appears to be comparable to obsessive-compulsive disorder and some substance-related addictions, but lower than compulsive buying and higher than problem gambling. Gaming disorder prevalence rates appear to be inflated by methodological characteristics, particularly measurement and sampling issues.

Genetics of OCD and Related Disorders; Searching for Shared Factors

Obsessive compulsive disorder (OCD) and several other obsessive-compulsive related disorders (OCRDs) including hoarding disorder, body dysmorphic disorder (BDD), skin picking disorder, trichotillomania and the newly arising public health conditions of online gaming and gambling disorders, under the umbrella of Problematic Usage of the Internet (PUI), not only share some common phenotypes, but there is evidence to suggest share some genetic risk factors. The simple fact that these disorders segregate within families points to this notion. However, the current data are still scarce. This chapter focuses on identifying the shared genetic factors. To address this question, a systematic review of the literature investigating genetic findings in OCD and OCRDs including PUI was conducted, with a focus on their genetic similarities. Greater knowledge of the specific genetic risks shared among OCRDs would be expected to open new avenues in the understanding of the biological mechanisms causing the development of these phenotypes, as well as provide opportunities to develop new animal and cellular models testing new therapy avenues.

Molecular genetics of neurotransmitters and neuropeptides involved in Internet use disorders including first insights on a potential role of hypothalamus' oxytocin hormone

This chapter covers the phenomenon of Internet use disorders (IUDs) and putative associations with different neurotransmitter and neuropeptide systems. Genes coding for such messengers can be seen as an important starting point in the complicated quest to understand human behavior including new phenomena such as IUDs. Therefore, a special focus of this chapter will lie on individual differences in molecular genetic underpinnings of neurotransmitter and neuropeptide systems and their associations with individual differences in tendencies towards IUDs. By shedding light on these associations, putative predisposing molecular genetic factors for the emergence and maintenance of IUDs can be carved out. Therefore, first an introduction to IUDs and a model that can guide research on putative associations of IUDs with different specific neurotransmitters and neuropeptides will be presented. Subsequently, twin studies on the heritability of IUDs are reviewed. Finally, studies on differences in molecular genetic predispositions and their associations with differences in IUDs will be presented and discussed, including targets related to the dopaminergic and serotonergic system as well as the hypothalamic neuropeptide oxytocin. The chapter closes with a conclusion about what is already known and what needs to be investigated in future studies to gain further insights into putative associations between molecular genetic markers and IUDs.

Children's Internet Use Profiles in Relation to Behavioral Problems in Lithuania, Latvia, and Taiwan

This study explored the profiles of elementary-school-aged children’s Internet use in relation to their emotional and behavioral problems. Participating in this cross-sectional study were 877 child–parent dyads from Latvia, Lithuania, and Taiwan. Children (8–10 years old) provided information on three variables: the amount of time they spent online, frequency of online activities, and knowledge of how to do things online. Latent profile analysis including these three variables provided a four-class solution for child Internet use. A comparison between Latvia, Lithuania, and Taiwan on the percentage of the sample distribution in each class showed that there was no difference between sites for the high class (high ratings on all three variables). The largest differences were for the low and average classes (low and average ratings on all three variables, namely, time online, frequency, and knowledge): the Lithuanian and Taiwanese samples were similar in that a higher percentage of each sample was in the low class, whereas the Latvian sample had children equally distributed between the low class and the average class. Analysis of the data from the entire sample for differences in parent-reported child behavioral difficulties suggested that children in the high class had an elevated level of behavioral problems and compulsive Internet use.

The Psychosocial Factors of Elementary School-Aged Children’s Compulsive Internet Use As Reported by Children and Parents

Children’s electronic media use in the form of Internet has increased over the past decades. The activities that children engage using the Internet can lead to experiencing positive as well as negative outcomes. Recent studies have found that excessive time devoted to the Internet use and behavioral narrowing can lead to Internet addiction (Enagandula et al., 2018) or compulsive Internet use (Meerkerk et al., 2009). This phenomenon can be described as a greater risk of developing excessive online habits, which may result in impairments of individual’s activities of daily living as well as relationships with others. Specific characteristics of these associations, however, have been examined only minimally in young children. The goal of this study was to examine the peculiarities of elementary school-aged children’s Internet use in relation to sociodemographic and relationships with others, as well as possible behavioral and emotional difficulties. The sample consisted of 304 parent-child dyads. All children in the study were second or third grade students (mean age 8.47 years, SD = 0.56), 50.3% were boys. Children and parents completed the Compulsive Internet Use Scale (CIUS; Meerkerk et al., 2009) and provided information about time spent on the Internet. Parents provided sociodemographic information and completed the Strengths and Difficulties Questionnaire (SDQ; Goodman, 1997), and children answered questions about their relationships with their parents and peers. The results of the study revealed significant gender differences in compulsivity of the Internet use, i.e. the estimates of boys CIUS – both provided by children and their parents – were significantly higher than girls. In overall, there was good agreement between parental and children’s reports on child’s CIUS, however parents reported higher CIUS scores and longer Internet use than children themselves. Regression analysis revealed that children’s CIUS is predicted (a) from the child’s perspective – by longer Internet time together with lower scores of child prosocial behavior, male gender, less advantaged financial situation in the family, and poorer parent-child relationships; (b) from the parent’s perspective – by longer Internet time, male gender, lower scores of child prosocial behavior, higher scores of behavioral and emotional difficulties together with less advantaged financial family status. The findings of the study are discussed in light of evidence-based practice and research.

Problematic internet use: an exploration of associations between cognition and COMT rs4818, rs4680 haplotypes

OBJECTIVE

Problematic internet users suffer from impairment in a variety of cognitive domains. Research suggests that COMT haplotypes exert differential effects on cognition. We sought to investigate differences in the genetic profiles of problematic internet users and whether those could shed light on potential cognitive differences.

METHODS

We recruited 206 non-treatment seeking participants with heightened impulsive traits and obtained cross-sectional demographic, clinical, and cognitive data as well as the genetic haplotypes of COMT rs4680 and rs4818. We identified 24 participants who presented with problematic internet use (PIU) and compared PIU and non-PIU participants using one-way analysis of variance (ANOVA) and chi square as appropriate.

RESULTS

PIU was associated with worse performance on decision making, rapid visual processing, and spatial working memory tasks. Genetic variants were associated with altered cognitive performance, but rates of PIU did not statistically differ for particular haplotypes of COMT.

CONCLUSION

This study indicates that PIU is characterized by deficits in decision making and working memory domains; it also provides evidence for elevated impulsive responses and impaired target detection on a sustained attention task, which is a novel area worth exploring further in future work. The effects observed in the genetic influences on cognition of PIU subjects imply that the genetic heritable components of PIU may not lie within the genetic loci influencing COMT function and cognitive performance; or that the genetic component in PIU involves many genetic polymorphisms each conferring only a small effect.

Neurobiological Risk Factors for the Development of Internet Addiction in Adolescents

The sudden appearance and spread of Internet addiction in adolescent populations, in association with the rapid escalation of consumed Internet content and the broad availability of smartphones and tablets with Internet access, is posing a new challenge for classical addictology which requires urgent solutions. Like the majority of other psychopathological conditions, pathological Internet addiction depends upon a group of multifactor polygenic conditions. For each specific case, there is a unique combination of inherited characteristics (nervous tissue structure, secretion, degradation, and reception of neuromediators), and many are extra-environment factors (family-related, social, and ethnic-cultural). One of the main challenges in the development of the bio-psychosocial model of Internet addiction is to determine which genes and neuromediators are responsible for increased addiction susceptibility. This information will herald the start of a search for new therapeutic targets and the development of early prevention strategies, including the assessment of genetic risk levels. This review summarizes the literature and currently available knowledge related to neurobiological risk factors regarding Internet addiction in adolescents. Genetic, neurochemical and neuroimaging data are presented with links to actual pathogenetic hypotheses according to the bio-psychosocial model of IA forming.

Manifesto for a European research network into Problematic Usage of the Internet

The Internet is now all-pervasive across much of the globe. While it has positive uses (e.g. prompt access to information, rapid news dissemination), many individuals develop Problematic Use of the Internet (PUI), an umbrella term incorporating a range of repetitive impairing behaviours. The Internet can act as a conduit for, and may contribute to, functionally impairing behaviours including excessive and compulsive video gaming, compulsive sexual behaviour, buying, gambling, streaming or social networks use. There is growing public and National health authority concern about the health and societal costs of PUI across the lifespan. Gaming Disorder is being considered for inclusion as a mental disorder in diagnostic classification systems, and was listed in the ICD-11 version released for consideration by Member States (http://www.who.int/classifications/icd/revision/timeline/en/). More research is needed into disorder definitions, validation of clinical tools, prevalence, clinical parameters, brain-based biology, socio-health-economic impact, and empirically validated intervention and policy approaches. Potential cultural differences in the magnitudes and natures of types and patterns of PUI need to be better understood, to inform optimal health policy and service development. To this end, the EU under Horizon 2020 has launched a new four-year European Cooperation in Science and Technology (COST) Action Programme (CA 16207), bringing together scientists and clinicians from across the fields of impulsive, compulsive, and addictive disorders, to advance networked interdisciplinary research into PUI across Europe and beyond, ultimately seeking to inform regulatory policies and clinical practice. This paper describes nine critical and achievable research priorities identified by the Network, needed in order to advance understanding of PUI, with a view towards identifying vulnerable individuals for early intervention. The network shall enable collaborative research networks, shared multinational databases, multicentre studies and joint publications.

Behavioral Addictions as Mental Disorders: To Be or Not To Be?

Should excessive and problematic engagement in nonsubstance use behaviors be mental disorders? The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) repositioned gambling disorder in the substance use disorders section and introduced Internet gaming disorder in the research appendix; the International Classification of Diseases (ICD-11) is also considering it. This article outlines pros and cons of considering behavioral addictions as mental disorders and also reviews the DSM-5 decision-making processes. It focuses on three conditions: gambling disorder, Internet gaming disorder (IGD), and Internet addiction (IA). We detail assessment methods and prevalence rates for these conditions and outline psychiatric comorbidities, demographic and biological risk factors, and promising treatment approaches. We also briefly discuss other putative behavioral addictions: eating/food, sex, exercise, shopping, and tanning "addictions." Overall, data are inconclusive, and consistent terminology and methodology are needed to define and evaluate these conditions more fully prior to considering them mental disorders.

Circulating MicroRNA Expression Levels Associated With Internet Gaming Disorder

BACKGROUND

Addictive use of the Internet and online games is a potential psychiatric disorder termed Internet gaming disorder (IGD). Altered microRNA (miRNA) expression profiles have been reported in blood and brain tissue of patients with certain psychiatric disorders and suggested as biomarkers. However, there have been no reports on blood miRNA profiles in IGD.

METHODS

To discover IGD-associated miRNAs, we analyzed the miRNA expression profiles of 51 samples (25 IGD and 26 controls) using the TaqMan Low Density miRNA Array. For validation, we performed quantitative reverse transcription PCR with 36 independent samples (20 IGD and 16 controls).

RESULTS

Through discovery and independent validation, we identified three miRNAs (hsa-miR-200c-3p, hsa-miR-26b-5p, hsa-miR-652-3p) that were significantly downregulated in the IGD group. Individuals with all three miRNA alterations had a much higher risk of IGD than those with no alteration [odds ratio (OR) 22, 95% CI 2.29-211.11], and the ORs increased dose dependently with number of altered miRNAs. The predicted target genes of the three miRNAs were associated with neural pathways. We explored the protein expression of the three downstream target genes by western blot and confirmed that expression of GABRB2 and DPYSL2 was significantly higher in the IGD group.

CONCLUSION

We observed that expressions of hsa-miR-200c-3p, hsa-miR-26b-5p, and hsa-miR-652-3p were downregulated in the IGD patients. Our results will be helpful to understand the pathophysiology of IGD.

The association between the nicotinic acetylcholine receptor α4 subunit gene (CHRNA4) rs1044396 and Internet gaming disorder in Korean male adults

The primary aim of this study was to investigate the genetic predisposition of Internet gaming disorder (IGD), and the secondary aim was to compare the results to those of alcohol dependence (AD). Two independent case-control studies were conducted. A total of 30 male participants with IGD, diagnosed according to the 5^th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria, and 30 sex-matched controls participated in study 1. We designed targeted exome sequencing (TES) to test for 72 candidate genes that have been implicated in the pathogenesis of addiction. The genes included seven neurotransmitter (dopamine, serotonin, glutamate, r-aminobutyric acid (GABA), norepinephrine, acetylcholine, and opioid) system genes. A total of 31 male in-patients with AD and 29 normal male controls (NC) were enrolled in study 2. The same 72 genes included in study 1 and ten additional genes related to alcohol-metabolic enzyme were selected as the target genes, and we identified the genetic variants using the same method (TES). The IGD group had a lower frequency of the T allele of rs1044396 in the nicotinic acetylcholine receptor alpha 4 subunit (CHRNA4), and this variant represents a protective allele against IGD. However, we did not find a significant difference in the polymorphisms of the 72 genes that encode neurotransmitter systems between the AD and NC groups. This study demonstrated that rs1044396 of CHRNA4 was significantly associated with IGD.

Merging Theoretical Models and Therapy Approaches in the Context of Internet Gaming Disorder: A Personal Perspective

Although, it is not yet officially recognized as a clinical entity which is diagnosable, Internet Gaming Disorder (IGD) has been included in section III for further study in the DSM-5 by the American Psychiatric Association (APA, 2013). This is important because there is increasing evidence that people of all ages, in particular teens and young adults, are facing very real and sometimes very severe consequences in daily life resulting from an addictive use of online games. This article summarizes general aspects of IGD including diagnostic criteria and arguments for the classification as an addictive disorder including evidence from neurobiological studies. Based on previous theoretical considerations and empirical findings, this paper examines the use of one recently proposed model, the Interaction of Person-Affect-Cognition-Execution (I-PACE) model, for inspiring future research and for developing new treatment protocols for IGD. The I-PACE model is a theoretical framework that explains symptoms of Internet addiction by looking at interactions between predisposing factors, moderators, and mediators in combination with reduced executive functioning and diminished decision making. Finally, the paper discusses how current treatment protocols focusing on Cognitive-Behavioral Therapy for Internet addiction (CBT-IA) fit with the processes hypothesized in the I-PACE model.

ICD-11 Gaming Disorder: Needed and just in time or dangerous and much too early?

In their debate contribution, Aarseth et al. (2016) strongly argue against the proposal of WHO ICD-11 (International Classification of Diseases, 11th revision) to include Gaming Disorder as a new diagnostic category emphasizing the fact that no consensus exists on the definition and the risk that gaming will be demonized and gamers stigmatized resulting in a tsunami of false positive referrals to treatment. In this commentary, it is argued that gaming is indeed just another relatively innocent recreational activity with only a small minority losing control resulting in gaming-related problems. It is also argued that - despite a lack of full consensus on the diagnostic criteria - there are clear indications that Gaming Disorder is a relevant clinical entity worldwide and that official recognition as a mental disorder is urgently needed to facilitate the further development, accessibility, and reimbursement of the treatment.

Excessive internet use in young women: What are the implications?

PURPOSE OF REVIEW

There are considerable gender differences in youth engaging in excessive internet use (EIU). This review provides updates based on the recent literature focusing on the EIU in young women to describe its implications including what it constitutes of, its correlates, sequelae and preventive and/or treatment strategies.

RECENT FINDINGS

Definition of EIU and its conceptualization still requires refinement. Recent studies indicate a changing trend towards female predominance of EIU. Women also differ in their internet use compared with men regarding their preference in the internet content and online activities, motives of use and factors related to access to the internet, including the device, sociocultural restrictions, etc. The correlates and sequelae of EIU encompass psychological, physical, biological, family and social domains that could form the basis of identifying individuals at risk and strategizing treatment.

SUMMARY

The findings indicate the need for standardization in definition and measures of EIU for better recognition of EIU and identification of its at-higher-risk females. Effective preventive and treatment measures are still limited by various methodology flaws outlined here.

Predictors and the distal outcome of general Internet use: The identification of children's developmental trajectories

This study examined the predictors and distal outcome in relation to the frequency of online activities and investigated the presence of prototypical trajectories following different patterns of general Internet use over 5 years. The data set consisted of a nationally representative sample of 2,840 fourth graders (M_age  = 9.86 years) in South Korea at baseline. Analyses revealed rank-order stability in general Internet use with four latent classes: high stable (5.8%), high quadratic (20.3%), moderate stable (32.7%), and low stable (41.2%). Youth with higher levels of perceived parental monitoring knowledge, friendship closeness, and depressed mood at baseline were more likely to belong to the high stable class, while girls were more likely to be in the high quadratic or moderate stable classes relative to the low stable class. The high stable class had the greatest odds of reporting alcohol use at grade eight, whereas the low stable class had the lowest odds. Statement of contribution What is already known on this subject? Internet usage increases as children progress through to early adolescence and then levels off Longitudinal data have shown that adolescents' greater Internet use is predictive of their higher levels of drinking What does this study add? To explore different developmental pathways of Internet use in relation to its antecedents and distal outcome Early adolescents who spend more time on the Internet have a greater chance of starting to drink The interindividual rank-order stability of general Internet usage exists at least before late childhood.

Internet addiction and its facets: The role of genetics and the relation to self-directedness

A growing body of research focuses on problematic behavior patterns related to the use of the Internet to identify contextual as well as individual risk factors of this new phenomenon called Internet addiction (IA). IA can be described as a multidimensional syndrome comprising aspects such as craving, development of tolerance, loss of control and negative consequences. Given that previous research on other addictive behaviors showed substantial heritability, it can be expected that the vulnerability to IA may also be due to a person's genetic predisposition. However, it is questionable whether distinct components of IA have different etiologies. Using data from a sample of adult monozygotic and dizygotic twins and non-twin siblings (N=784 individuals, N=355 complete pairs, M=30.30years), we investigated the magnitude of genetic and environmental influences on generalized IA as well as on specific facets such as excessive use, self-regulation, preference for online social interaction or negative consequences. To explain the heritability in IA, we further examined the relation to Self-Directedness as potential mediating source. Results showed that relative contributions of genetic influences vary considerable for different components of IA. For generalized IA factors, individual differences could be explained by shared and non-shared environmental influences while genetic influences did not play a role. For specific facets of IA and private Internet use in hours per week, heritability estimates ranged between 21% and 44%. Bivariate analysis indicated that Self-Directedness accounted for 20% to 65% of the genetic variance in specific IA facets through overlapping genetic pathways. Implications for future research are discussed.

Personalized Media: A Genetically Informative Investigation of Individual Differences in Online Media Use

Online media use has become an increasingly important behavioral domain over the past decade. However, studies into the etiology of individual differences in media use have focused primarily on pathological use. Here, for the first time, we test the genetic influences on online media use in a UK representative sample of 16 year old twins, who were assessed on time spent on educational (N = 2,585 twin pairs) and entertainment websites (N = 2,614 twin pairs), time spent gaming online (N = 2,635 twin pairs), and Facebook use (N = 4,333 twin pairs). Heritability was substantial for all forms of online media use, ranging from 34% for educational sites to 37% for entertainment sites and 39% for gaming. Furthermore, genetics accounted for 24% of the variance in Facebook use. Our results support an active model of the environment, where young people choose their online engagements in line with their genetic propensities.

An association study of Taq1A ANKK1 and C957T and - 141C DRD2 polymorphisms in adults with internet gaming disorder: a pilot study

BACKGROUND

Though Internet gaming disorder (IGD) is considered to share similar genetic vulnerability with substance addictions, little has been explored about the role of the genetic variants on IGD. This pilot study was designed to investigate the association of the Taq1A polymorphism of the ankyrin repeat and kinase domain containing 1 (ANKK1) gene and C957T and - 141C of the dopamine D2 receptor (DRD2) with IGD and their role on the personality and temperament traits in IGD among adult population.

METHODS

Sixty-three subjects with IGD and 87 control subjects who regularly played Internet games were recruited. Self-administered questionnaires on self-control, dysfunctional impulsivity, and temperament and character domains were done. The Taq1A ANKK1 and the C957T and - 141C ins/del from the DRD2 genes were genotyped using the specific TaqMan PCR assay.

RESULTS

The distributions of allele and genotype frequencies were not significantly different between the IGD and control groups in both genders. In male, excessive gaming and use of gaming to escape from a negative feeling were associated with the del- genotype of the - 141C. Among IGD, the del+ genotype was associated with higher novelty seeking. Logistic regression showed no predictive value of these polymorphisms for IGD when using age and gender as covariates.

CONCLUSIONS

Though no direct association of the Taq1A ANKK1 and C957T DRD2 variants with IGD were observed, the - 141C polymorphism may play a role in IGD via mediating symptoms or temperament traits.

The 2D:4D Marker and Different Forms of Internet Use Disorder

Internet use disorder (IUD) presents a growing problem worldwide. Among others, it manifests in loss of control over Internet usage and social problems due to problematic Internet use. Although IUD currently is not an official diagnosis in DSM-5 or ICD-10, mounting evidence suggests that IUD indeed could be categorized as a behavioral addiction. On a systemic neuroscientific level, IUD is well characterized and dysfunctions in the fronto-striatal-limbic loop have been observed in persons being afflicted with IUD. On a molecular level underlying these neural dysfunctions less is known. Therefore, the present research investigates the influence of prenatal testosterone as measured via the 2D:4D marker of the hand on IUD. Testosterone represents an interesting hormonal marker, because sex differences in IUD have been observed, e.g., males show higher tendencies toward Internet gaming disorder (IGD) or females toward overusage of online social networks (both compared to the contrary sex). In N = 217 participants associations between the 2D:4D marker of the hand and both unspecified IUD and specific forms of IUD were investigated. It appeared that more female hands (right side; characterized by higher digit ratio of the index to the ring finger, i.e., >1, meaning lower prenatal testosterone) were associated with lower IGD (rho = -0.17, p = 0.01, N = 211). This effect was driven by the facet of loss of control of Internet Gaming in the whole sample (rho = -0.20, p < 0.01, N = 211) and the female subsample (rho = -0.20, p = 0.02, N(f) = 137). Aside from this, a negative association appeared between the facet of loss of control of generalized IUD and the right digit ratio in males underlining earlier work. In sum, the present work demonstrates that the 2D:4D marker is an interesting marker for Internet addiction and can be easily included as a biomarker to understand the biological underpinnings of Internet (over-)usage.

Computer addiction and computer literacy: two sides of the same process

The article provides evidence that the educational system at its current state is not able to adequately perceive the intervention of informational computer technologies and utilize them, as well as clearly differentiate types and risks of the so-called computer addiction. So far, education hasn’t developed a clear view of the role these technologies play in educational process, it only notifies their ambiguity for teaching different subjects. It means that humanity is still in search of the new approaches, being under the pressure of the old paradigms in education. It is especially obvious in teachers’ training practice, equipment of educational institutions, and other factors. The authors believe that contemporary risks in education, connected with intervention of information technologies, can be managed through computer literacy of participants in the educational process, and it might become a sort of a counterbalance for computer addiction.

An Affective Neuroscience Framework for the Molecular Study of Internet Addiction

Internet addiction represents an emerging global health issue. Increasing efforts have been made to characterize risk factors for the development of Internet addiction and consequences of excessive Internet use. During the last years, classic research approaches from psychology considering personality variables as vulnerability factor, especially in conjunction with neuroscience approaches such as brain imaging, have led to coherent theoretical conceptualizations of Internet addiction. Although such conceptualizations can be valuable aid, the research field is currently lacking a comprehensive framework for determining brain-based and neurochemical markers of Internet addiction. The present work aims at providing a framework on the molecular level as a basis for future research on the neural and behavioral level, in order to facilitate a comprehensive neurobiological model of Internet addiction and its clinical symptomatology. To help establish such a molecular framework for the study of Internet addiction, we investigated in N = 680 participants associations between individual differences in tendencies toward Internet addiction measured by the Generalized Problematic Internet Use Scale-2 (GPIUS-2) and individual differences in primary emotional systems as assessed by the Affective Neuroscience Personality Scales (ANPS). Regression analysis revealed that the ANPS scales FEAR and SADNESS were the ANPS scales most robustly positively linked to several (sub)scales of the GPIUS-2. Also the scales SEEKING, CARE and PLAY explain variance in some of the GPIUS-2 subscales. As such, these scales are negatively linked to the GPIUS-2 subscales. As the ANPS has been constructed on substantial available brain data including an extensive molecular body with respect to evolutionary highly conserved emotional circuitry in the ancient mammalian brain, the present study gives first ideas on putative molecular mechanisms underlying different facets of Internet addiction as derived from associations between tendencies toward Internet addiction and individual differences in primary emotional systems. For example, as SADNESS is linked to the overall GPIUS-2 score, and the neuropeptide oxytocin is known to downregulate SADNESS, it is conceivable that the neuropeptide might play a role in Internet addition on the molecular level. Our findings provide a theoretical framework potentially illuminating the molecular underpinnings of Internet addiction. Finally, we also present data on the ANPS and smartphone addiction at the end of the paper. Similar to the reported associations between the ANPS and the GPIUS-2, these correlations might provide an initial outline for a framework guiding future studies that aim to address the molecular basis of smartphone addiction.

Problematic internet use (PIU): Associations with the impulsive-compulsive spectrum. An application of machine learning in psychiatry

Problematic internet use is common, functionally impairing, and in need of further study. Its relationship with obsessive-compulsive and impulsive disorders is unclear. Our objective was to evaluate whether problematic internet use can be predicted from recognised forms of impulsive and compulsive traits and symptomatology. We recruited volunteers aged 18 and older using media advertisements at two sites (Chicago USA, and Stellenbosch, South Africa) to complete an extensive online survey. State-of-the-art out-of-sample evaluation of machine learning predictive models was used, which included Logistic Regression, Random Forests and Naïve Bayes. Problematic internet use was identified using the Internet Addiction Test (IAT). 2006 complete cases were analysed, of whom 181 (9.0%) had moderate/severe problematic internet use. Using Logistic Regression and Naïve Bayes we produced a classification prediction with a receiver operating characteristic area under the curve (ROC-AUC) of 0.83 (SD 0.03) whereas using a Random Forests algorithm the prediction ROC-AUC was 0.84 (SD 0.03) [all three models superior to baseline models p < 0.0001]. The models showed robust transfer between the study sites in all validation sets [p < 0.0001]. Prediction of problematic internet use was possible using specific measures of impulsivity and compulsivity in a population of volunteers. Moreover, this study offers proof-of-concept in support of using machine learning in psychiatry to demonstrate replicability of results across geographically and culturally distinct settings.

Does acceptance of power distance influence propensities for problematic Internet use? Evidence from a cross-cultural study

INTRODUCTION

Several studies suggest that Asian countries are particularly afflicted by problematic Internet use (PIU).

METHODS

The present study investigates whether individual differences in the acceptance of power distance can be linked to overuse of the Internet in Germany and in China. Power distance has been discussed as an essential dimension on which Asian and Western societies differ. In the present study, we investigate two large non-clinical samples from Germany (n = 297) and China (n = 556) to address this question.

RESULTS

Both in Germany and in China, high acceptance of power distance was positively associated with PIU. These effects were more pronounced in China compared with Germany. Moreover, the observed effects were stronger in males compared with females.

DISCUSSION

Clearly, these findings are just a starting point and need to be replicated in the future. Clinical populations and a further important difference variable - collectivism - also merit consideration in future work.

Targeted exome sequencing for the identification of a protective variant against Internet gaming disorder at rs2229910 of neurotrophic tyrosine kinase receptor, type 3 (NTRK3): A pilot study

Background and aims Internet gaming disorder (IGD) has gained recognition as a potential new diagnosis in the fifth revision of the Diagnostic and Statistical Manual of Mental Disorders, but genetic evidence supporting this disorder remains scarce. Methods In this study, targeted exome sequencing was conducted in 30 IGD patients and 30 control subjects with a focus on genes linked to various neurotransmitters associated with substance and non-substance addictions, depression, and attention deficit hyperactivity disorder. Results rs2229910 of neurotrophic tyrosine kinase receptor, type 3 (NTRK3) was the only single nucleotide polymorphism (SNP) that exhibited a significantly different minor allele frequency in IGD subjects compared to controls (p = .01932), suggesting that this SNP has a protective effect against IGD (odds ratio = 0.1541). The presence of this potentially protective allele was also associated with less time spent on Internet gaming and lower scores on the Young's Internet Addiction Test and Korean Internet Addiction Proneness Scale for Adults. Conclusions The results of this first targeted exome sequencing study of IGD subjects indicate that rs2229910 of NTRK3 is a genetic variant that is significantly related to IGD. These findings may have significant implications for future research investigating the genetics of IGD and other behavioral addictions.

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.

The Genetic and Environmental Contributions to Internet Use and Associations With Psychopathology: A Twin Study

Excessive internet use has been linked to psychopathology. Therefore, understanding the genetic and environmental risks underpinning internet use and their relation to psychopathology is important. This study aims to explore the genetic and environmental etiology of internet use measures and their associations with internalizing disorders and substance use disorders. The sample included 2,059 monozygotic (MZ) and dizygotic (DZ) young adult twins from the Brisbane Longitudinal Twin Study (BLTS). Younger participants reported more frequent internet use, while women were more likely to use the internet for interpersonal communication. Familial aggregation in 'frequency of internet use' was entirely explained by additive genetic factors accounting for 41% of the variance. Familial aggregation in 'frequency of use after 11 pm', 'using the internet to contact peers', and 'using the internet primarily to access social networking sites' was attributable to varying combinations of additive genetic and shared environmental factors. In terms of psychopathology, there were no significant associations between internet use measures and major depression (MD), but there were positive significant associations between 'frequency of internet use' and 'frequency of use after 11 pm' with social phobia (SP). 'Using the internet to contact peers' was positively associated with alcohol abuse, whereas 'using the internet to contact peers' and 'using the internet primarily to access social networking sites' were negatively associated with cannabis use disorders and nicotine symptoms. Individual differences in internet use can be attributable to varying degrees of genetic and environmental risks. Despite some significant associations of small effect, variation in internet use appears mostly unrelated to psychopathology.