This study was conducted to determine the risk factors for Internet addiction levels in adolescents aged 13–19 years. In this nested case–control study, a total of 71 adolescents with problematic internet usage (PIU), identified as scoring "50 and above" on the Young Internet Addiction Scale, were categorized as the PIU group. Additionally, 70 adolescents with normal internet usage (NIU) were selected for the control group, matching the criteria of same gender, age, grade, and school characteristics. It was found to be 4.86 (95% CI: 2.04–11.57) of being in the problematic Internet use group in those who used the Internet for “5 hours or more” per day compared to others. Those who considered themselves Internet addicts had a 4.29 (95% CI: 1.44–12.74) of being in the problematic Internet use group. Furthermore, individuals who used the Internet for “virtual chat” purposes had a 2.73 (95% CI: 1.12–6.64) of being in the problematic Internet use group, while those who did not use “science and technology” websites had a 5.35 times higher risk (95% CI: 1.50–19.03) compared to users who did. Moreover, a 1-unit increase in the “Trait Anxiety” Inventory total score resulted in a 1.06 times higher risk (95% CI: 1.01–1.11) of being in the problematic Internet use group.

Keywords: Adolescent health, behavioral addiction, nested case–control, problematic Internet use, risk factors