Relative Immaturity in Childhood and Attention-Deficit/Hyperactivity Disorder Symptoms From Childhood to Early Adulthood: Exploring Genetic and Environmental Overlap Across Development

The results show that RI is significantly associated with ADHD symptoms, particularly during childhood and adolescence, and that the association is primarily explained by a shared genetic liability. Nevertheless, the magnitude of associations across development was modest, highlighting that RI is merely one aspect contributing to the complex etiology of ADHD symptoms.