Brief reportDepression like characteristics of 5HTTLPR polymorphism and temperament in excessive internet users
Introduction
The phenomenon of excessive internet use as a distinct entity within the addictive disorders continues to be the subject of debate (Kraut et al., 1998, Mitchell, 2000, Campbell et al., 2006). However, studies have shown that the addiction-like qualities of EIU may be responsible for behavioral problems including social isolation, depressed mood, and unstable impulsivity (Young, 1998, Reirdan, 1999). These symptoms are similar to those found in depression and anxiety disorders (Kraut et al., 1998, Shapira et al., 2000, Moody, 2001). In an association study between excessive internet use and depression, Kraut et al. (1998) showed that subjects with excessive internet use demonstrated loneliness, decline in communication with household family members and social withdrawal. Major depression is known to be one of the most common comorbid psychiatric disorders in Korean adolescents with EIU (Ha et al., 2006). Ha et al. (2007) also reported that adolescents with excessive internet use had high harm avoidance, low self-directedness, low cooperativeness and high self-transcendence, which are all seen in depression.
The serotonin reuptake transporter gene (5HTT) located on chromosome 17q11.1-q12 has a functional polymorphism in the variable repeat sequence in the promoter region (5HTTLPR) (Ramamoorthy et al., 1993, Lesch et al., 1996). 5HTTLPR may be important in the fine-regulation of serotonergic neurotransmission; the homozygous long allelic variant (L) is associated with higher concentrations of 5HTT messenger RNA and a greater rate of reuptake than variants containing the short allelic variant (S) (Lesch et al., 1996, Greenberg et al., 1999). These findings have led to suggestions that this 5HTTLPR polymorphism (specially, the presence of the S allele of 5HTTLPR) may play a key role in the etiology of depression (Blier and de Montigny, 1999, Wrase et al., 2006) and substance dependence (Lesch, 2005).
The Temperament and Character Inventory (TCI), developed by Cloninger and colleagues, has been widely used in research on psychobiological human behavior (Cloninger, 1987). Among the four dimensions of temperament, novelty seeking and harm avoidance are thought to be correlated with depression (Serretti et al., 2006, Jylha and Isometsa, 2006). Serretti et al. (2006) reported that S allele homozygote of 5HTTLPR was associated with low novelty seeking scores in mood disorder patients. Jylha and Isometsa (2006) demonstrated that harm avoidance is associated with depressive and anxiety symptoms in a normal population. Recently, Ha et al. (2007) also reported the association of harm avoidance and excessive internet use in adolescents with excessive internet use.
Based on these studies, we hypothesized that the EIU group will have characteristics similar to those of patients with depressive disorder in terms of genetic distribution and the harm avoidance dimension of TCI. To the best of our knowledge this is the first genetic polymorphism study of the serotonin and norepinephrine systems in EIU subjects.
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Materials and methods
The design of this study was carried out in two phases. Subjects were first screened using self-report questionnaires and the Internet Addiction Scale (IAS)(Young, 1998). Two psychiatrists then conducted the interview with the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Health Disorders-IV (SCID) (with emphasis on the pathological gambling criteria) and assess subjects for the presence of other psychiatric disorders (D.H.H and Y.S.L; inter rater reliability (n =
Results
There was no significant difference with regard to age and education years between the EIU and control groups (Table 1). The mean time of internet use, the mean Young's internet addiction scale score and the mean BDI score of the EIU group were 2.2 ± 1.7 h/day, 68.8 ± 10.5, and 9.0 ± 3.0, respectively. The mean time of internet use, the mean Young's internet addiction scale score, and BDI score of the control group were 0.8 ± 0.39 h/day, 27.00 ± 4.13, and 6.2 ± 2.16, respectively.
The homozygous short
Discussion
In current results, short allele 5HTTLPR homozygote and higher harm avoidance were related with excessive internet use. The BDI scores in excessive internet use group were also higher than that in healthy comparisons.
Serotonergic neurotransmission has been a major focus of pharmacological treatment of mood and anxiety disorders (Blier and de Montigny, 1999). Several in vitro and postmortem studies have explored the role of 5HTTLPR polymorphism and the reuptake of synaptic serotonin (Little et
Role of funding source
Funding for this study was provided by the Korean Ministry of Health and Welfare Grant KMH2004. However, the Korean Ministry of Health and Welfare had no further role in study design; in the collection, analysis and interpretation of data; in the writing of the report; or in the decision to submit the paper for publication.
Conflict of interest
All authors are agreed not to have any actual or potential conflict of interest including any financial, personal or other relationships with other people or organizations within three (3) years of beginning the work submitted that could inappropriately influence, or be perceived to influence, our work.
Acknowledgements
We thank Dr. Chang Hyun Kim and Sang Wook Kim,who kindly provided the data necessary for our analysis.
References (31)
- et al.
Serotonin and drug-induced therapeutic responses in major depression, obsessive–compulsive and panic disorders
Neuropsychopharmacology
(1999) - et al.
Borderline personality disorder in major depression: symptomatology, temperament, character, differential drug response, and 6-month outcome
Compr. Psychiatry
(2003) - et al.
Temperament, character and symptoms of anxiety and depression in the general population
Eur. Psychiatry
(2006) Alcohol dependence and gene x environment interaction in emotion regulation: is serotonin the link?
Eur. J. Pharmacol.
(2005)Internet addiction: genuine diagnosis or not?
Lancet
(2000)- et al.
Psychiatric features of individuals with problematic internet use
J. Affect. Disord.
(2000) - et al.
Reliability and validity of the Korean version of the Temperament and Character Inventory
Compr. Psychiatry
(2002) - et al.
Internet use by the socially fearful: addiction or therapy?
Cyberpsychol. Behav.
(2006) A systematic method for clinical description and classification of personality variants. A proposal
Arch. Gen. Psychiatry
(1987)- et al.
A psychobiological model of temperament and character
Arch. Gen. Psychiatry
(1993)
A sib-pair study of the Temperament and Character Inventory scales in major depression
Arch. Gen. Psychiatry
Genetic variation in the serotonin transporter promoter region affects serotonin uptake in human blood platelets
Am. J. Med. Genet.
Psychiatric comorbidity assessed in Korean children and adolescents who screen positive for Internet addiction
J. Clin. Psychiatry
Depression and Internet addiction in adolescents
Psychopathology
The validity and reliability of Beck Depressive inventory Korean version
J. Korea. Neuropsychiatr. Assoc.
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