Academic performance, study time, psychological factors, and substance use among Korean adolescents.

Substance use and mental health problems often emerge during adolescence. However, relatively few large-scale studies have examined how academic and psychological factors jointly relate to substance use among adolescents in high-pressure educational contexts. This study investigated the associations between perceived academic performance, daily study time, psychological factors (stress, anxiety, and happiness), and alcohol and tobacco use among Korean adolescents. We analyzed the cross-sectional data of 50,914 middle and high school students who participated in the 2023 Korea Youth Risk Behavior Survey. Substance use was defined as any alcohol or tobacco use in the past 30 days. Hierarchical logistic regression models estimated the associations between sociodemographic, psychological, and academic variables and substance use, and interaction terms tested whether the associations between academic performance, study time, and substance use differed across levels of psychological factors. Overall, 12.5% of adolescents reported recent substance use. Higher stress and anxiety and lower happiness were associated with greater odds of use, whereas higher academic performance and longer daily study time were independently associated with lower odds of use. Anxiety and happiness showed small but significant interactions with academic factors, although negative associations between academic performance, study time, and substance use were maintained across levels of psychological functioning. These findings highlight the potential relevance of academic engagement and emotional well-being for school-based strategies to address adolescent substance use in competitive educational contexts such as Korea.