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ORIGINAL ARTICLE
Ahead of print publication  

An exploratory study on the psychological and epigenetic correlates of internet addiction


1 Faculty of Psychology, International Telematic University Uninettuno, Rome, Italy
2 Department of Clinical and Dynamic Psychology, University of Rome, Rome, Italy
3 Clinical Psychologist & Research Associate Desousa Foundation, Lokmanya Tilak Municipal Medical College, Mumbai, Maharashtra, India
4 Department of Psychiatry, Lokmanya Tilak Municipal Medical College, Mumbai, Maharashtra, India

Date of Submission23-Jan-2021
Date of Acceptance25-Jan-2021
Date of Web Publication09-Mar-2021

Correspondence Address:
Sagar Karia,
OPD 21,Department of Psychiatry, New OPD Building, 2nd Floor, Lokmanya Tilak Municipal Medical College and G.H., Sion, Mumbai - 400 022, Maharashtra
India
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/aip.aip_13_21

  Abstract 


Background: The dopamine active transporter (DAT) gene has been implicated in various psychiatric disorders such as attention-deficit hyperactivity disorder and externalizing behaviors. Studies on the methylation loci of DAT and Internet addiction (IA) are sparse. The study aimed to look at the association between various methylation loci of the DAT gene and IA, impulsivity, and other related variables. Methodology: Thirty-two youths with 10/10 genotype of DAT gene were administered the IA Test, Barratt's Impulsivity Scale (BIS), and Adult Self-Report Scale and using buccal swab methylation loci 1–7 of DAT gene were assessed. The data were analyzed by a correlation between various variables and a multiple regression analysis. Results: It was noted that the met5 allele (r = 0.844, P < 0.01) and met7 allele (r = 0.517, P = 0.01) correlated with DAT MEDIA scores. The total scores on the BIS and Internet Addiction Scale (IAS) also showed a positive correlation (r = 0.641, P = 0.01). Positive correlations were also noted between the scores on IAS and rule-breaking behavior as well as withdrawn behavior. Similar positive correlations were found between total scores on the BIS and rule-breaking behavior, withdrawn behavior, and intrusive behavior. Conclusions: Further studies in larger samples are needed to draw conclusions on the relationship between DAT gene methylation loci and IA or impulsivity.

Keywords: Dopamine active transporter, impulsivity, Internet addiction, met5 allele, met7 allele, methylation loci



How to cite this URL:
Cerniglia L, Cimino S, Lodha P, Karia S, Desousa A. An exploratory study on the psychological and epigenetic correlates of internet addiction. Ann Indian Psychiatry [Epub ahead of print] [cited 2021 Apr 20]. Available from: https://www.anip.co.in/preprintarticle.asp?id=311032




  Introduction Top


Half of the world's population has access to the Internet and uses it for entertainment, work, social interaction, and several other purposes.[1] Although the Web has been originally intended to simplify and improve everyday life, according to Griffiths' definition of “technological addictions,”[2] research has widely reported negative consequences due to its excessive and/or maladaptive use.[3] These outcomes may include loss of control over the time spent on the Internet, social and relational problems produced by the preference for being online rather than interact in face-to-face activities, impaired school or work results connected with neglecting these realms, and negative health consequences, again associated with a disproportionate time spent online.[4] Problematic Internet use has not so far been defined as clinical diagnosis; rather, it is currently considered as a potentially pathological behavioral pattern characterized by loss of control over the behavior, conflict (internal and interpersonal), preoccupation with the Internet, use of the Web to modify mood, and withdrawal symptoms.[5]

In young adulthood, Internet addiction (IA) has been correlated with co-occurring symptoms of anxiety, psychological distress, impulsiveness, and depression.[6] Other authors have suggested that youths could use the Internet as a coping reaction to emotional or social difficulties when they lack family, peers, and social support.[7] Besides the possible comorbidities between IA and psychopathological risk, it has been posited that the dopamine active transporter (DAT) gene functioning and methylation could be associated with the problematic use of the Web.[8] In fact, dopamine has been recognized as having a crucial role in modulating the emotional/behavioral functioning, including reward and sensation seeking, aggression, and affiliative behaviors,[9] all aspects that have been linked with a problematic use of the Internet. In particular, individuals carrying a 10/10 repeat polymorphism in the DAT genotype are hypothesized as at higher risk for the above maladaptive outcomes. While the DAT genotype has been linked to attention-deficit hyperactivity disorder and externalizing behavior,[10],[11] there are no studies that have looked at its relationship to IA and impulsivity. Keeping that in mind, the aim of the current study was to find a relationship between various methylation loci of the DAT, IA, and impulsivity with other related factors.


  Methodology Top


The data for the study comprised 71 youths from a community sample with a median age of 23 years (M = 22.67, standard deviation: 0.359). The sample comprised males (n = 15) and females (n = 56), youth from Rome, Italy, who were assessed through the Internet Addiction Test (IAT),[12] Barratt's Impulsivity Scale (BIS),[13] and the Adult Self-Report (ASR).[14] Considering all data analyses we conducted, the number of participants we recruited was sufficient to obtain a statistical power of 0.80 for small-to-medium effect size and a critical alpha of 0.05 (two-tailed). A buccal swab with a saliva sample was also gathered from each participant, and the methylation of loci 1–7 was analyzed as reported in previous studies.[9] Before the start of the study, the institutional ethics committee authorized and approved the study. The data were collected between July and October 2018. The sample data were divided into two groups based on the genotype: 10/10 subgroup (n = 32) and non 10/10 subgroup (n = 39). Thirty-two youths of the 10/10 subgroup were used in the study analysis as this was the group shown to have a possible association with psychopathology in previous studies. The data were statistically analyzed using Pearson's correlation test and multiple regression analysis. All youths in the study explained the aims of the study, and their written valid consent for the same was obtained. This study used the STREGA report guidelines.[15] Laboratory methods including source and storage of DNA, genotyping methods, and platforms are described elsewhere.[9] Missing data (2%) were handled through multiple imputation method. All data were analyzed using IBM SPSS statistics, version 25 (IBM, New York, USA).


  Results Top


The descriptive statistical data for DAT, BIS, IAT, and ASR used in the study are shown in [Table 1].
Table 1: Descriptive statistical values

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A Pearson correlation (r) statistic was conducted between DAT, various alleles (met1, methylation locus 2 (met2), methylation locus 3 (met3), methylation locus 5 (met5), and methylation locus 7 (met7) of the DAT genes, and various scales (BIS and DAT) in order to understand any relationship that may be existent among the variables. [Table 2] shows the significant correlation values between the variables; the correlation values were found significant at alpha level 0.01 for a two-tailed test.
Table 2: Significant r

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It was noted that the met5 allele (r = 0.844, P < 0.01) and met7 allele (r = 0.517, P = 0.01) correlated with DAT scores. The total scores on the BIS and Internet Addiction Scale (IAS) also showed a positive correlation (r = 0.641, P = 0.01). Positive correlations were also noted between the scores on IAS and rule-breaking behavior (r = 0.688, P = 0.01) as well as withdrawn behavior (r = 0.637, P = 0.01). Similar positive correlations were found between total scores on the BIS and rule-breaking behavior (r = 0.634, P = 0.01), withdrawn behavior (r = 0.492, P = 0.01), and intrusive behavior (r = 0.472, P = 0.01). Rule-breaking behavior in the participants also correlated positively with intrusiveness (r = 0.586, P = 0.01) and aggressiveness (r = 0.471, P = 0.01). Aggressiveness in the participant showed a direct correlation with anxiety-depression (r = 0.553, P = 0.01) and thought problems (r = 0.658, P = 0.01).

A multiple regression analysis was carried out to ascertain whether DAT predicted any psychopathological behaviors. The results failed to find any significant finding to show if DAT or any of the alleles predicted the psychopathological variables.


  Discussion Top


The DAT gene has been proposed to play a significant role in behavioral and affective regulation.[16] Many child and adolescent psychiatric disorders have been reported in the literature to have a positive association with the DAT gene. This has been reported for attention-deficit disorder, oppositional defiant disorder, and autism spectrum disorders.[10],[11],[17] These are all disorders where impulsivity, aggression, and social withdrawal may be seen.

The present study is unique because it assesses the association between DAT genotype, its alleles, and DAT methylation in correlation to IA and behavioral impulsivity along with other psychopathological variables such as rule-breaking behavior, aggressive behavior, withdrawn behavior, somatic complaints, anxiety-depression, thought problems, attention problems, and intrusion among youths (males and females, median age = 23 years) in the 10/10 genotype group. Positive correlations were found between two methylation loci, i.e., met5 and met7, and DAT. None of the methylation loci studied or DAT correlated with any of the scores on the various scales (IAT and BIS) and psychopathological variables (as mentioned above) indicating no direct association (/positive correlation). The study is a small one and has only 32 youths with 10/10 genotype and hence may be inconclusive. A larger number of participants may have helped yield some positive results. However, the nature of the financial involvement needed in the study restricted the number of samples recruited. A minimum requirement of 30 samples was maintained, and keeping in mind that the prevalence of psychopathology as a result of DAT methylation in the 10/10 genotype group is yet in its initial explorations, a standard sample remains to be decided. Nevertheless, it is presently safe to consider that the greater size of sample will be more conducive to optimize the aforementioned associations with psychopathology. Rule-breaking behavior and withdrawn behavior correlated with IAT scores. It is well known that youths with IA may show a lack of regard for rules and oppositional behavior[18] as well as the IA may be a cause for social withdrawal and withdrawn behavior.[19] The same associations were noted for behavioral impulsivity scores and rule-breaking behavior, withdrawn behavior, and intrusiveness. Impulsivity has been linked to intrusiveness in some studies in the past.[20] In the present sample, the aggressiveness scores of the youth were linked to anxiety-depression and thought problems. Aggressive behavior may be a symptom on its own and may also be the manifestation of various thought disorders or a symptom of depression.[21] It is important that a positive correlation merely entails that the scores are related and does not mean a cause-and-effect relationship.

Multiple regression analysis yielded no positive associations between any of the variables. This indicates that none of the variables or scores on the scales were affected by DAT1 alleles or methylation. Studies on the DAT1 genotype have yielded mixed findings in the past[9],[22],[23] and larger studies are needed to ascertain findings that may be clinically useful. This is one of the first studies that have looked at the effects of DAT1 genotype and methylation loci on IA, behavioral impulsivity, and externalizing behaviors in relation to these two variables.


  Conclusions Top


The present study delineates that there is a positive association between met5 and met7 with DAT which was found among youths (n = 32) with 10/10 genotype. Contrasting to the sparsely reported earlier literature, there was no positive correlation found between any psychopathological variables as well as IAT and BIS scores with DAT and its alleles in the 10/10 genotype group which has earlier demonstrated to have a potential link in children aged 0–5 years as well as school-aged children and adolescents.[9] The study has various limitations. It is a small circumscribed study which is cross sectional. Longitudinal studies are needed to determine causal interactions if any. The interplay of genes, environmental factors, and epigenetics is complex in child and adolescent psychiatry. Further studies in varied samples focusing on specific disorders and specific variables with various DAT1 methylation variables are needed to formulate succinct causal correlations and apply these findings clinically.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

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Barratt ES. Impulsiveness and aggression. In: Monahan J, Steadman HJ, editors. Violence and Mental Disorder: Developments in Risk Assessment. Chicago, USA: University of Chicago Press; 1994. p. 61-79.  Back to cited text no. 13
    
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Little J, Higgins JP, Ioannidis JP, Moher D, Gagnon F, von Elm E, et al. STrengthening the REporting of Genetic Association Studies (STREGA) – An extension of the STROBE statement. Genet Epidemiol 2009;33:581-98.  Back to cited text no. 15
    
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Hamilton PJ, Campbell NG, Sharma S, Erreger K, Herborg Hansen F, Saunders C, et al. De novo mutation in the dopamine transporter gene associates dopamine dysfunction with autism spectrum disorder. Mol Psychiatry 2013;18:1315-23.  Back to cited text no. 17
    
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Jung YE, Leventhal B, Kim YS, Park TW, Lee SH, Lee M, et al. Cyberbullying, problematic internet use, and psychopathologic symptoms among Korean youth. Yonsei Med J 2014;55:826-30.  Back to cited text no. 18
    
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Todd RD, Huang H, Smalley SL, Nelson SF, Willcutt EG, Pennington BF, et al. Collaborative analysis of DRD4 and DAT genotypes in population-defined ADHD subtypes. J Child Psychol Psychiatry 2005;46:1067-73.  Back to cited text no. 23
    



 
 
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