Childhood autism rating scale--Tokyo version for screening pervasive developmental disorders.

To assess the utility of the Childhood Autism Rating Scale - Tokyo Version (CARS-TV), its total score was compared among 430 children with DSM-IV per subgroup (i.e. autistic disorder (AD), childhood disintegrative disorder (CDD), Asperger's disorder, and pervasive developmental disorders (PDD) not otherwise specified (PDDNOS)). Values of Cronbach's alpha were 0.91 for the PDD group and 0.89 for the non-PDD mental retardation (MR) group, and 0.93 for both groups combined. The total score was significantly higher in PDD (mean = 30.1, SD = 4.5) than in non-PDD MR (mean = 22.9, SD = 3.3), t(503) = 13.7, P< 0.0001. The cut-off to distinguish PDD from non-PDD MR was 25.5/26, with sensitivity, specificity, positive predictive value and negative predictive value of 0.86, 0.83, 0.97 and 0.50, respectively. The total score differed significantly among the four groups, with CDD and AD being significantly higher than both PDDNOS and Asperger's disorder, PDDNOS being significantly higher than Asperger's disorder and no significant difference between CDD and AD. The cut-off to distinguish AD from PDDNOS was 30/30.5, with sensitivity, specificity, positive predictive value and negative predictive value of 0.71, 0.75, 0.77 and 0.69, respectively. CARS-TV seems to be a useful instrument for differentiating between PDD and non-PDD MR and between AD and PDDNOS, although further replication is needed.