Increase of orexin A in the peripheral blood of adolescents with Internet gaming disorder

Mild internet use is associated with epigenetic alterations of key neurotransmission genes in salivary DNA of young university students

The potentially problematic use of the Internet is a growing concern worldwide, which causes and consequences are not completely understood yet. The neurobiology of Internet addiction (IA) has attracted much attention in scientific research, which is now focusing on identifying measurable biological markers. Aim of this study was to investigate epigenetic and genetic regulation of oxytocin receptor (OXTR), dopamine transporter (DAT1) and serotonin transporter (SERT) genes using DNA obtained from saliva samples of young university students: the Internet Addiction Test (IAT) was administered to evaluate the potential existence and intensity of IA. Significant changes in DNA methylation levels at OXTR, DAT1 and SERT genes were observed in the 30 < IAT < 49 group (mild-risk internet users) compared to the IAT < 29 subjects (complete control of internet use) and IAT > 50 subjects (considered as moderately addicted). Moreover, epigenetic markers were significantly correlated, either directly (for OXTR and DAT1) or inversely (OXTR and DAT1 versus SERT), to the psychometric properties. Our data confirmed the association of OXTR, DAT1 and SERT genes in processes related to behavioural addictions and might be of relevance to suggest possible biological predictors of altered behaviours and the eventual vulnerability to develop an IA. Different other genetic pathways have been suggested to play a role in IA and research is ongoing to better define them, in order to help in the early diagnosis as well as in the development of new potential treatments.

The Role of BDNF and NPY Levels, Effects of Behavioral Systems and Emotion Regulation on Internet Addiction in Adolescents

Internet addiction (IA), one of the behavioral addictions, is also related to impulsivity. Although studies on its etiology and risks continue, the number of studies is limited. In this study, we aimed to assess the roles of behavioral systems, emotional regulation (ER), and impulsivity in the development of IA in adolescents and also to assess the relationship between all these clinical parameters and brain-derived neurotrophic factor (BDNF) and neuropeptide Y (NPY). Forty-two adolescents with IA and 30 healthy controls (ages 12 -17) were included in the study. Self-reported measures included the Internet Addiction Scale. (IAS), Behavioral Activation and Behavioral Inhibition Scale (BAS/BIS), Barratt. Impulsiveness Scale-11 (BIS-11), and Difficulties in Emotion Regulation Scale-16 (DERS-16) were used for the assessment of the participants. The levels of plasma brain BDNF and NPY were evaluated with the ELISA method. BAS/BIS subscale scores, BIS-11, and DERS-16 scale total scores were found to be statistically significantly higher, while BDNF and NPY levels were found to be lower in adolescents with IA compared to the healthy controls. IA severity was not found to correlate with both BDNF and NPY. IA was found to be more related to BIS than to BAS. There is a need for further studies evaluating developmental features and possible diagnostic biomarkers that may be associated with IA in adolescents.

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.

[Increase in the level of orexin receptor 1 (OX1R) mRNA in the brain structures of rats prone to impulsivity in behavior]

Orexin and its receptors are involved in the mechanisms of pathological craving for alcohol and psychoactive drugs. The orexin system is also involved in the mechanisms of non-chemical forms of addiction: binge eating and gambling. The aim of this work was to study the level of orexin receptor mRNA in the hypothalamus, hippocampus, and prefrontal cortex of rats prone to impulsivity in behavior in a model for studying the elements of gambling addiction (a variant of the Iowa Gambling Task test). Brain structures were isolated on the 22nd day of the experiment. The expression of the OX1R gene was higher in the hypothalamus by 122% and in the hippocampus by 149% in rats that preferred to receive a high reward, but with a low probability as compared with a group of animals that preferred a low level of reinforcement, but with a 100% probability. In the prefrontal cortex, on the contrary, no significant changes were observed in the level of OX1R mRNA. The level of OX2R mRNA insignificantly changed in the hypothalamus, hippocampus, and prefrontal cortex of rats prone to impulsivity in behavior. The data indicate involvement of OX1R in the hypothalamus and hippocampus in mechanisms mediating impulsive behavior and the choice of the significance of positive reinforcement in terms of its varying strength and probability.

Biochemical Correlates of Video Game Use: From Physiology to Pathology. A Narrative Review

In the last few decades, video game playing progressively became a widespread activity for many people, in childhood as well in adulthood. An increasing amount of literature has focused on pathological and non-pathological correlates of video game playing, with specific attention towards Internet Gaming Disorder (IGD). While many neurobiological studies in this field were based on neuroimaging, highlighting structural and functional brain changes among video game users, only a limited number of studies investigated the presence of biochemical correlates of video gaming. The present work aims to summarize and review the available literature about biochemical changes linked to video game use in IGD patients as well as non-pathological users, and the differences in between. Results may shed light on risks and benefits of video games, providing directions for further research on IGD treatment and, on other hand, on the potential role of video games in therapeutic or preventive protocols for specific conditions.