Chapter 66: Neurodevelopmental Disorders

Each condition is evaluated through epidemiology, underlying neurobiological mechanisms, diagnostic criteria, and evidence-based management approaches. Attention deficit-hyperactivity disorder is characterized by persistent inattention, hyperactivity, and impulsivity, with strong genetic contributions and involvement of dopaminergic and noradrenergic dysregulation. First-line pharmacological treatment includes stimulant medications, though nonstimulants and behavioral interventions remain important, particularly in younger populations. Autism spectrum disorder involves core deficits in social reciprocity and communication alongside restricted, repetitive behaviors and interests, with onset typically evident by age two. While no pharmacological cure exists, applied behavioral analysis represents the primary intervention, with medications reserved for managing associated irritability or aggression. Intellectual disability encompasses deficits in both cognitive reasoning and adaptive functioning, classified by severity levels and requiring comprehensive neuropsychological assessment alongside individualized support systems. Tic disorders, exemplified by Tourette's disorder, involve involuntary motor and vocal manifestations that fluctuate in intensity and frequency, often improving substantially during adolescence. Management approaches vary considerably across these conditions, ranging from stimulant pharmacotherapy and behavioral parent training for attention deficit-hyperactivity disorder to habit reversal therapy and alpha-agonist medications for tic disorders. Understanding the developmental trajectories, neurobiological substrates, and evidence-based interventions for each disorder enables clinicians and educators to provide comprehensive, developmentally informed care throughout the lifespan.