Depression and Anxiety Symptoms Among Kenyan Adolescents: Psychometric Validation, Prevalence Patterns, Network Analysis, and Psychosocial Determinants

Background: Adolescent mental health in Sub-Saharan Africa remains critically understudied despite high burden estimates. Here, we assessed the psychometric properties of Western-derived instruments, prevalence of depression and anxiety symptoms, association with psychosocial and socio-demographic factors, and symptom network structures in a large multi-year sample of Kenyan adolescents. Methods: We administered depression (PHQ-8), anxiety (GAD-7), social support, perceived control, and wellbeing measures to 7,865 Kenyan secondary school students aged 13-20 across three studies (2021-2023). Results: Both PHQ-8 (α = 0.70) and GAD-7 (α = 0.78) showed adequate reliability. Factor analyses yielded 1-factor structures with good model fit (PHQ-8: RMSEA=0.052, CFI=0.945; GAD-7: RMSEA=0.056, CFI=0.970). Overall, 30.3% and 25.1% met clinical cut-offs for depression and anxiety, respectively, with striking temporal variation: prevalence peaked in 2021 (41.9% depression, 37.7% anxiety), decreased in 2022, then partially rebounded in 2023. Mixed-effects modeling revealed social support (B = -0.10 for depression, B = -0.11 for anxiety) and perceived control (B = -0.27 for depression, B = -0.22 for anxiety) as robust protective factors. Final school year students showed elevated risk (B = 1.41 for depression, B = 1.36 for anxiety). Students in girls' schools demonstrated significantly higher symptoms (B = 1.57 for depression, B = 1.48 for anxiety) compared to mixed-gender schools. Contrary to expectations, minority tribal status showed no significant associations with either depression or anxiety symptoms. Academic performance demonstrated clear dose-response relationships, with excellent performance associated with substantially lower depression (B = -2.54) and anxiety (B = -1.78) symptoms. Network analysis identified worry-related anxiety symptoms as most central, with hopelessness and nervousness serving as key bridges between depression and anxiety domains. Elevated-symptom groups showed higher network connectivity (global strength = 3.58 vs 3.26). Multidomain analysis revealed optimism as the most central variable across psychological domains. Discussion: Western-derived measures met psychometric standards with Kenyan adolescents. Depression and anxiety showed high prevalence with pandemic-related temporal patterns and significant associations with academic stress, school environment, and psychosocial resources. The elevated symptoms in girls' schools highlight important environmental factors requiring further investigation. Network findings identify potential intervention targets and demonstrate how mental health symptoms embed within broader psychological systems in this understudied population