Background: Both DSM-IV and the ICD-10 exclude diagnosis of attention deficit/hyperactivity disorder (ADHD) when autism diagnostic is present. Some authors suggest, however, that autism can be associated to other comorbidity amongst which the ADHD.
Objective: To estimate prevalence of ADHD in children with autism.
Method: Children were selected from a specialized school, all of then had previous diagnosis or diagnostic suspicion of autism. The Brazilian version of the KIDDIE-SADS PL was applied to parents for diagnostic of ADHD. DSM-IV diagnostic of autism was based on parents' interview and child observation.
Results: 32 children were included in the study. Results show that 53.1% of the ASD child had ADHD symptoms enough to fulfill DSM-IV diagnostic criteria, whereas 56.9% did not fulfill DSM-IV criteria for ADHD.
Conclusion: Results suggest a high frequency of ADHD symptoms in ASD patients. Elucidating if we are facing a comorbity or an autism distinct phenotype can contribute for a more adjusted pharmacotherapy approach for these children.