Cognitive Profiles of Preschool Children with Developmental Coordination Disorders and ADHD Studies confirm that developmental coordination disorders (DCD) are often accompanied by ADHD. It is important to know why children with combined disorders show a special profile in a common intelligence test (WPPSI-III). For this purpose, the WPPSI-III results of a total of 125 children aged five to six years with diagnosed isolated DCD, isolated ADHD, combined disorders and a normative sample were compared. Children with isolated ADHD showed the best cognitive profile. Children of all three diagnosis subgroups presented significantly poorer abilities in all WPPSI-III scales than the normative sample. In comparison with preschoolers showing isolated ADHD, children with DCD and ADHD have a significant lower Processing Speed Quotient.