NEUROBIOLOGY OF ADHD IN CHILDREN AND ADOLESCENTS: A LITERATURE BASED REVIEW

Abstract

Attention Deficit Hyperactivity Disorder (ADHD) is a chronic neurobehavioral disorder whose clinical presentation alters across development. This review examines the direct relationship between underlying neurobiological mechanisms and age-related differences in ADHD manifestations between children and adolescents. Structurally, a narrative review with a systematic approach was conducted primarily using PubMed (supplemented by Google Scholar) for literature published between 2016 and 2026. Following a rigorous screening of 182 initial records, a qualitative thematic synthesis was applied to 30 peer-reviewed articles (28 for primary analysis and 2 for supplementary context) alongside 2 manually included academic textbooks. Findings reveal that delayed brain maturation and dysfunction of dopaminergic and noradrenergic neurotransmitters, combined with reduced neural flexibility between the Default Mode Network (DMN) and Executive Control Network (ECN), underpin these age-specific variations. These mechanisms directly drive the clinical shift from overt hyperactivity and impulsivity in childhood to predominant inattention, executive dysfunction, and emotional dysregulation in adolescence. In conclusion, understanding the developmental neurobiology of ADHD is clinically paramount for improving diagnostic accuracy and designing individualized management strategies. Clinicians must move beyond static treatments and adopt age-developmentally appropriate multimodal approaches that integrate targeted pharmacology and tailored psychosocial support to enhance patients' overall quality of life.