Roles of Hostility and Depression in the Association between the MAOA Gene Polymorphism and Internet Gaming Disorder

The metabolism of bioamine in the central nervous system contributes to the development of addiction. We examined the roles of hostility and depression in the association between internet gaming disorder (IGD) and monoamine oxidase-A (MAOA) EcoRV polymorphism (rs1137070). A total of 69 adults with IGD and 138 without IGD were recruited through diagnostic interviewing. We evaluated participants for rs1137070, depression, and hostility. The participants with the TT genotype of rs1137070 had a higher odds ratio of 2.52 (1.37–4.64) for IGD compared with the C carriers. Expressive hostility behavior and hostility cognition mediated the association between rs1137070 and IGD. Indicating lower MAOA activity, the TT genotype predicted IGD and higher expressive hostility behavior and hostility cognition. Expressive hostility behavior and hostility cognition may underline the association between rs1137070 and IGD. Assessment of and intervention for hostility behavior and cognition should be provided to attenuate the risk of IGD, particularly in those with the TT genotype. Further brain imaging or neurobiological studies are required to elucidate the possible mechanism underlying the association between MAOA activity and IGD.

Biological Determinants of Hostility

Our aim was to study the association of hostility with the DRD4, DAT, MAOA genes in an open male population of 25–64 years old. A representative sample of men aged 25–64 years (n = 657 men, average age 44.3 ± 0.4 years) was examined in 1994–1995 and 45–64 years old (n = 781 men, average age - 56.48 ± 0.2 years) in 2003–2005 using the methods proposed by the WHO international program “MONICA-psychosocial” and “HAPIEE”. All respondents completed the hostility questionnaire on their own. Genotyping of the DRD4, DAT and MAOA gene polymorphisms was carried out. It was established that the level of hostility in the male population was 76.9% in the group of 25–64 years old and 60.3% in the group of 45–64 years old. Genotypes 4/6, 4/7 of the DRD4 gene are reliably associated with a high level of hostility; the genotype 4/4 of the DRD4 gene is associated with an average and lower level of hostility. There was no association of individual genotypes and VNTR alleles of DAT gene polymorphism with different levels of hostility. It was found that among individuals with low-active alleles of the MAOA-L gene (alleles 2 and 3), a high level of hostility was more common - 50.9%. The results of constructing a logistic regression model showed that the presence of low-active alleles (2; 3) of the MAOA gene increases the likelihood of hostility OR = 2.103 (95% CI 1.137–3.889, p = 0.018). Based on the received data we can assume that the long alleles of the DRD4 gene and the low-level allele of the MAOA-L gene are associated with hostility.

The Effects of Childhood Maltreatment on Non-Suicidal Self-Injury in Male Adolescents: The Moderating Roles of the Monoamine Oxidase A (MAOA) Gene and the Catechol-O-Methyltransferase (COMT) Gene

(1) Background: Numerous studies suggest strong associations between childhood maltreatment and nonsuicidal self-injury (NSSI); this is also true for the roles of dopaminergic genes in the etiology of some psychopathologies related to NSSI. Investigating the interactions of environments and genes is important in order to better understand the etiology of NSSI. (2) Methods: Within a sample of 269 Chinese male adolescents (Mage = 14.72, SD = 0.92), childhood maltreatment and NSSI were evaluated, and saliva samples were collected for MAOA T941G and COMT Val158Met polymorphism analyses. (3) Results: The results revealed no primary effects attributable to MAOA T941G and COMT Val158Met polymorphism on NSSI. However, there was a significant three-way interaction between MAOA, COMT, and child abuse (β = −0.34, p < 0.01) in adolescent NSSI. Except for carriers of the T allele of MAOA and the Met allele of COMT, all studied male adolescents displayed higher NSSI scores when exposed to a higher level of child abuse. A similar three-way interaction was not observed in the case of child neglect. (4) Conclusions: The results indicate that the MAOA gene and COMT gene play moderating roles in the association between child abuse and NSSI of male adolescents and suggest the polygenic underpinnings of NSSI.

The Effect of MAOA Gene × Gender on the Relationship between Negative Network News Browsing Preference and Aggression among College Students

The present research aims to examine whether and how the negative network news browsing preference (NNNBP) affect individual’s aggression. Two studies were conducted in the current research: study 1 developed a new measurement scale—network news browsing preference questionnaire(NNBPQ). The results indicated it had appropriate reliability (Cronbach’s α = 0.93) and validity (χ 2 /df = 1.92, CFI = 0.94, NFI = 0.89, GFI = 0.89，TLI = 0.94，RMSEA = 0.05) , which was conformed to psychometrics standards, and could be used for further study. Study 2 explored the relationship between NNNBP and aggression, and the moderate effect of MAOA gene × gender among 352 college students. The results indicated that: (a) NNNBP could positively predict male college students’ hostility and total score. It also could positively predict female college students’ physical aggression, verbal aggression, hostility and total score. (b) MAOA Gene × gender had moderate effect on the relationship between NNNBP and aggression; more specially, NNNBP could positively predict female G allele carriers’ physical aggression and hostility, while didn’t show significant under other conditions. Finally, the limitations and future prospects of the present research were discussed.

Association Analysis of Monoamine Oxidase-A Gene Promoter Polymorphism (MAOA uVNTR) for Antisocial Behavior: Absence of the Counting Number Repeats in Central Iran

Background: The MAOA gene is located on the X chromosome (Xp11.23). Several studies have established a VNTR (Variable Number Tandem Repeat) polymorphism in the upstream of the MAOA gene transcriptional initiation region named uVNTR which is correlated with the risk of antisocial behavior. Objectives: This study aimed to investigate the association between MAOA genotypes and the risk of violent behavior in a cohort of violent and age-matched non-violent individuals. Methods: In the current case-control study, MAOA uVNTR was genotyped in a cohort of 88 violent and 95 age-matched non-violent individuals. Individuals were genotyped for the MAOA uVNTR by performing PCR, gel electrophoresis, and sequencing. Furthermore, a chi-square test was performed using SPSS, and a p-value of less than 0.05 was considered statistically significant. Results: We identified three MAOA uVNTR allelic variants: They were harboring 3.5, 4.5, and 5.5 repeated sequences. Alleles with 2, 3, 4, 5, and 6 repeats were not observed in any of the two examined groups. Conclusions: We did not detect a statistically appreciable association between antisocial behavior and allele frequencies in the studied population in central Iran.

Association of MAOA-uVNTR gene polymorphism with hostility in an open population of males aged 45-64 in Russia / Siberia (international program: WHO «MONICA-psychosocial», «HAPIEE»)

Objective: to study the association of hostility with high and low-active variants of the MAOA gene in an open population of men 45-64 years old. Using the methods proposed by the WHO International Program “MONICA-psychosocial” and “HAPIEE”, a representative sample of men aged 45–64 years old (n = 781 men, average age was 56.48 ± 0.2 years) in 2003-2005. All respondents independently completed a questionnaire on hostility. From the surveyed sample, using the random number method, 156 men were selected who were genotyped for MAOA-uVNTR polymorphism. It was approved that the level of hostility in the population of men was 60.3%. It was revealed that among persons with low-active alleles of the MAOA-L gene (allele 2 and 3) a high level of hostility was more common — 50.9%. The results of building a logistic regression model showed that the presence of low-active alleles (2; 3) of the MAOA gene increases the likelihood of hostility OR = 2,103 (95% CI 1,137-3,889, p = 0.018). The results obtained allow us to conclude that the low-active allele of the MAOA-L gene is associated with hostility.

Genetic interaction between two VNTRs in the MAOA gene is associated with the nicotine dependence

Nicotine dependence is an addiction to tobacco products and a global public health concern that in part would be influenced by our genetics. Smokers are reported to have reduced MAOA activity, but the results from genetic associations with this gene have been inconclusive. Two functionally relevant variable number tandem repeat (VNTR) domains, termed uVNTR and dVNTR, in the MAOA gene are well characterized transcriptional regulatory elements. In the present study, we analyzed uVNTR and dVNTR polymorphisms in the MAOA gene in the Vietnamese male population of smokers and non-smokers in order to assess the association of MAOA with the nicotine dependence measured by the Fagerström Test for Nicotine Dependence (FTND). Individual analysis of VNTRs separately identified uVNTR to be associated with the F6 question of the FTND indicating the stronger addiction to nicotine. No associations were found between the dVNTR and smoking behavior. The combination of dVNTR and uVNTR, that predicts low expression of MAOA (10–3 haplotypes), was significantly associated with the higher nicotine dependence (FTND score), longer smoking duration, and more persistent smoking behavior (fewer quit attempts). In conclusion, our study confirms that low MAOA expression is genetically predictive to the higher nicotine dependence. Impact statement The present study combined the analysis of two transcriptional regulators, uVNTR and dVNTR, in the MAOA gene that is an enzyme responsible for the monoamine degradation and identified genetic interaction between these VNTRs in association with the nicotine dependence. The main impact is that when analyzing different populations in the genetic studies, the functionally meaningful variants should be combined rather than addressing individual elements separately (a mini polygenic risk score for a particular gene/locus). This combination is very rarely analyzed and therefore the study sets an example. Another impact is that we analyzed the genetic variability in the Asian population and therefore our data present a piece of information from underrepresented populations.