Co-morbidity and factor analysis on attention deficit hyperactivity disorder and autism spectrum disorder DSM-IV-derived items

Background: there is a gap in the literature regarding the extent of possible co-occurrence of attention deficit hyperactivity disorder (adhd) and pervasive developmental disorders (pdd). this study aimed to investigate co-occurring of adhd in children with pdd. methods: a clinical sample of 68 children with pdd was assessed according to dsm-iv criteria to make adhd and/ or pdd diagnoses. all the different types of pdd were included. dsm-iv derived criteria for adhd and pdd were analyzed. an exploratory factor analysis was conducted. results: the rate of autism, asperger syndrome, rett’s disorder, childhood disintegrative disorder and pdd-nos (not otherwise specified) was 55.4%, 16.9%, 3.1%, 3.1%, 21.5%, respectively. 53.8% of the sample was with adhd co-morbidity. the rate of adhd subtypes was 37.1%, 22.9%, and 40.0% for inattentive type, hyperactivity/impulsivity type and combined type, respectively. conclusion: adhd and its symptoms highly co-occur with pdd. meanwhile, the result of factor analysis supports the independence of adhd and pdd diagnostic criteria.