Genetic and environmental influences on problematic Internet use: A twin study

Despite many studies on the prevalence and correlates of problematic Internet use (PIU), we know little about its etiological components. Our main aim is to find out to what extent PIU is influenced by genetic and environmental factors using the classic twin design. A total of 237 Turkish twin-pairs aged 10-25 participated in the study. Pill was measured using the 'Problematic Internet Use Scale' (PIUS) developed by Ceyhan, Ceyhan and Gurcan. For male twin-pairs, the monozygotic (MZ) twin correlations were larger than the dizygotic (DZ) twin correlations, indicating that genetic factors influenced scores on the PIUS. However, for female twin-pairs, the MZ correlations were smaller than the DZ correlations for the PIUS, showing that genetic factors did not play a role in female twin-pairs. The influence of both genetic and environmental factors was explored with model-fitting analysis. Results showed that both for the "social comfort/benefit" and "negative consequences associated with the Internet use" sub-dimensions, the best-fitting models were the ADE models whereas both for the "excessive use" sub-dimension and "PIUS-Total", the best-fittings models were the ACE models. The key result of this study is that the genetic and non-shared environmental effects are equally influential on the overall PIU in male twin-pairs. (C) 2014 Elsevier Ltd. All rights reserved.