Citation for published version (APA): Brikell, I., Kuja-Halkola, R., Larsson, J-O., Lahey, B. B., Kuntsi, J., Lichtenstein, P., ... Larsson, H. (2016). Relative Immaturity in Childhood and Attention-Deficit/Hyperactivity Disorder Symptoms From Childhood to Early Adulthood: Exploring Genetic and Environmental Overlap Across Development. Journal of the American Academy of Child and Adolescent Psy...