Adolescent Insomnia Disorder - Problematic Internet Use Nexus: A Convergent Developmental Trajectory - Bridging Neuroimaging Biomarkers, Molecular Susceptibility, and Environmental-Neurocognitive Cascades.

Adolescent Insomnia Disorder (ID) and Problematic Internet Use (PIU) represent a pressing global public health challenge, frequently co-occurring and synergistically impacting mental and physical well-being. Despite their high comorbidity, a comprehensive integrative model elucidating their shared pathophysiology is lacking. This review is the first to propose a Convergent Developmental Trajectory Model, which posits that ID and PIU in adolescents are sustained by a self-reinforcing cycle driven by the dynamic interplay of three core components: (a) a shared biological vulnerability stemming from adolescent-specific neurodevelopment and molecular genetics; (b) common environmental triggers, such as academic stress and adverse childhood experiences; and (c) neurocognitive reinforcement through impaired inhibitory control and dysregulated reward processing. We synthesize converging evidence from neuroimaging, molecular studies, and environmental psychology to demonstrate how these components interact within the adolescent developmental context to perpetuate a vicious cycle. The model underscores that effective interventions must target these shared pathways, for instance, by developing transdiagnostic Cognitive Behavioral Therapy (CBT) protocols specifically designed for ID-PIU comorbidity. Future research should prioritize longitudinal neurodevelopmental studies and multi-omics profiling to enable early risk stratification and personalized approaches. Addressing this complex issue requires interdisciplinary collaboration to formulate precision therapies and evidence-based public health policies.