The search for genetic risk markers of Internet addiction (IA) involves two methodological approaches: 1) comparison of the groups with or without IA to identify “categorical” risk markers of IA based on qualitative psychometric characteristics of the research participants; 2) studying a sufficiently large cohort of participants to analyze the association between genetic markers and severity of signs and symptoms of IA as quantitative variables, which makes it possible to identify "dimensional" IA markers for assessing possible preclinical forms of the disease that do not reach the IA level for categorical psychometric assessment, while the level and variety of behavioral symptoms of IA may be significant. To assess the severity of IA, Chinese Internet Addiction Scale (CIAS) was used. Purpose of the study: to analyze the association between subscale scores and integral indicators of the CIAS and genetic variants of the testing panel to identify possible dimensional genetic markers of the risk of Internet dependency in young adults, regardless of the diagnosis and taking into account gender effects. The study included 433 individuals (30.9% females), mean [±SD] age, 24.63±4.75 years. The cohort consisted of 215 healthy participants, 127 people with alcohol dependence (AD) and 91 individuals with IA. The study was carried out using a genetic testing panel (31 polymorphic loci in 22 genes), formed on the basis of a pathogenetic approach. In females, both the total CIAS scores (p=0.004) and the scores on all CIAS subscales and integral indicators of CIAS were higher than in males, except the CIAS_IH (Interpersonal and Health-related Problems). The diagnosis of AD did not make significant differences in the distribution of the CIAS scores in the studied sample. A number of genetic predictors of subscale scores and integral indicators of CIAS were identified, which can be considered as dimensional risk markers for Internet dependency domains in young adults. The specificity of genetic markers for IA and the absence of significant associations with AD were shown. The greatest contribution was made by markers associated with the dopamine neurotransmitter system as an essential element of the brain reward system. Markers associated with GABA/glutamate system had a significant, but limited to female sex effect. A minimum number of genetic markers was found for integral indicators such as "Key symptoms of IA" and total scores of CIAS, and a maximum number of genetic markers was identified for the subscale "Compulsive symptoms of IA", which may reflect an important contribution of genetic (biological) factors to the level of addiction severity. The identified genetic dimensional risk markers for various domains of Internet-dependent behavior can be useful for assessing the risk of developing preclinical forms of IA.