ADHD and comorbidity in Swedish school age children ADHD and comorbidity in Swedish school age children.37 MR, mental retardation; RWD, reading/writing disorder; DC, developmental coordination; ODD, oppositional defiant disorder. ADHD and comorbidity in Swedish school age children.37 MR, mental retardation; RWD, reading/writing disorder; DC, developmental coordination; ODD, oppositional defiant disorder. V A Harpin Arch Dis Child 2005;90:i2-i7 Copyright © BMJ Publishing Group Ltd & Royal College of Paediatrics and Child Health. All rights reserved.