The Impact of Socioeconomic Inequality on Mental Health among Adolescents in Qazvin, Iran: Blinder-Oaxaca Decomposition Method

BACKGROUND: Mental health is integral to public health in adolescents. Although previous studies have shown that low socioeconomic status (SES) is associated with mental disorders (MD), it is unclear which mental health domains are most important. Thus, our study aimed to investigate the associations between 5 domains of mental disorder and SES inequality in adolescents. METHODS: We conducted a cross-sectional study among adolescents (N = 1724). Associations between SES inequality with mental disorders, such as emotional symptoms, conduct problems, hyperactivity, peer relationship problems, and prosocial behavior, were examined. We used the concentration index (CI) to determine inequality. The gap between the low and high socioeconomic groups was decomposed into its determinants using the Blinder-Oaxaca decomposition method. RESULTS: Mental health's overall CI was –0.085 (P ˂ 0.001). The emotional problem was primarily caused by SES inequality (–0.094 [P = 0.004]). Decomposition of the gap between the 2 economic groups showed that physical activity, school performance, exercise, parents' smoking status, and gender were the most important determinants of inequality. CONCLUSION: SES inequality plays a vital role in adolescents' mental health. It seems that the emotional problem domain of mental health might be more amenable to interventions than other domains.