The impact of primary mental healthcare on core symptoms of depression among underrepresented adolescents: A network analysis perspective

Background: Depression has emerged as a leading contribution of the global mental health burden, particularly among underrepresented adolescents. Despite the World Health Organization's promotion of primary mental healthcare as a critical solution, its real-world effectiveness in low- and middle-income countries remains debated due to high costs and insufficient follow-up. This study aimed to explore the impact of primary mental healthcare on the core symptoms of adolescent depression using network analysis, while examining the influence of demographic factors such as gender, age, and family support, to identify more precise and targeted intervention strategies, improving its effectiveness. Methods: A citywide, multi-center, longitudinal cohort study was conducted in Nanchong, Sichuan Province, China, involving 73,750 adolescents (34,606 girls and 39,144 boys) with median age of 14.00 years old. The Comprehensive Primary Healthcare for Adolescents Program (CPHG) involved two rounds of psychological screening and early intervention. Depressive symptoms were assessed using the Center for Epidemiological Studies Depression Scale (CES-D). Network analysis was employed to map the interrelations between depressive symptoms and evaluate the intervention's impact. Results: The CPHG program significantly reduced CES-D median scores from 6.00 to 2.00 (p < 0.001). Network analysis revealed changes in the structure and centrality of depressive symptoms post-intervention, with specific symptoms such as sadness (C18) showing consistent reductions across subgroups. Gender disparities were evident, with female adolescents exhibiting stronger symptom interconnectivity. Junior high school students also demonstrated a more robust symptom network compared to senior high school students. Adolescents living in social welfare institutions exhibited higher global expected influence of depressive symptoms than those living with both parents. Conclusions: Primary mental healthcare interventions effectively modify the network structure of depressive symptoms in adolescents, with specific symptoms like sadness being critical targets for intervention. Gender and grade-level differences highlight the need for tailored mental healthcare strategies. The findings underscore the importance of addressing both core and peripheral symptoms to enhance treatment efficacy and reduce the severity and recurrence of depression among underrepresented adolescents.