There is little study about attention deficit hyperactivity Symptoms in children with PDD In the present study we evaluated the co-occurrence rate of ADHD and its subtypes according to DSM-IV-TR in children with high functioning PDD.

Participants were recruited from the consecutive referrals to the child and adolescent psychiatric clinics in Ebne Sina and Sheikh Hospital, Mashhad, Iran. We selected 3–12 year old individuals who had PDD according to DSM IV-TR who had verbal or performance IQ of 70 or higher on WISC-III. The diagnosis was made by a certified child and adolescent psychiatrist. Subjects were divided into two age groups (children aged 3–7 and children aged 8–12). Forty children with the mentioned criteria were included in the sample.

Among 40 subjects 31 children 22 boys and 9 girls (77/5%) met the DSM- IV-TR diagnostic criteria for ADHD. Fifteen children with combined type (37/5%), 11 with predominantly inattentive type (27/5%) and 5 with predominantly hyperactive impulsive type (12/5%). The co occurrence rate of ADHD with PDD subtypes were 69/5 For Autistic Disorder and 51/5 For As /PPD NOS without a statistical significant difference (P = 0/078). The co occurrence rate of ADHD in 2 age groups were 36/3 (20 of 31) for the older group and 66/7 (11 of 31) for the younger group without a statistical Significant difference (P = 0/5). Discussion: The high co occurrence rate of ADHD in children with Autism spectrum disorder found in our study strongly indicates a clinical need to assess AD/HD symptoms in children with PDD.