Internet-addiction (IA) is one of the most common non-chemical (or behavioral) addictions with genetic impact and substantial effects of psychological and personality characteristics, taking into account the childhood traumatic experience. Gene-environment interactions (GxE) may substantially impact on the risk of Internet-addiction (IA).

Aim: to test the associations between the functional polymorphism rs6265 (Val66Met) in brain-derived neurotrophic factor (BDNF) gene, affecting BDNF function, and childhood traumatic experience and their GxE interactions with IA risk.

In total 456 participants were screened with Chinese Internet Addiction Scale (CIAS) to cut a cohort on two groups: IA (CIAS total score ≥ 65, n=100) and controls (CIAS total score less 64, n=356). The Adverse Childhood Experiences International Questionnaire (ACE-IQ) was used to assess childhood traumatic experience using its main domains: parents (P), family (F), abuse (A) and violence (V). BDNF Val158Met polymorphism was detected by RT-PCR.

Logistic regression revealed associations of P scores with increased IA risk only after adjustment for sex and age (p=0.01, OR=1.166, 95%CI[1.038-1.309]) and V scores with decreased IA risk (p=0.000, OR=0.799, 95%CI [0,233;0,744] only before adjustment. No associations of F and A with IA risk were found. BDNF Val158Met per se was not associated with IA risk, but significant effect of interaction V score*BDNF rs6265 CC on IA risk in “protective” manner was revealed (р=0.039, OR=0.873, 95%CI[0.768-0.993]) in a model adjusted for sex and age.

Childhood violence experience interacts with BDNF Val158Met polymorphism and CC (ValVal) genotype may be possibly protective factor decreasing the internet addiction risk

This work was carried out with the financial support of the Russian Foundation for Basic Research: RFBR grant # 18-29-22079