At least two studies describe the role of genetic polymorphisms in internet addiction and excessive internet use. These genetic variants include:
1. SS-5HTTLPR variant (homozygous short allelic variant of the serotonin transporter gene)
2. T-variant (CC genotype) of the rs1044396 polymorphism on the CHRNA4 gene
References:
Depression like characteristics of 5HTTLPR polymorphism and temperament in excessive internet users. (Link)
The Role of the CHRNA4 Gene in Internet Addiction: A Case-control Study. (Link)
