Differential diagnosis between attention-deficit/hyperactivity disorder and pervasive developmental disorder--not otherwise specified.

The lack of clarity in diagnostic classification and the lack of specificity of assessment devices deter accurate identification of children with Pervasive Developmental Disorder-Not Otherwise Specified (PDD--NOS). The current study was designed to assess the utility of the Personality Inventory for Children (PIC) and the Conners Parent Rating Scale (CPRS-48) in differentiating PDD--NOS from Attention Deficit Hyperactivity Disorder (ADHD), disorders with overlapping symptom constellations. Subjects were 44 children recruited from a tertiary-care center with the diagnosis of ADHD or PDD--NOS. Results showed significant differences between groups on PIC scales assessing internalizing behaviors, social skills, and unusual affect and behavior. There were no group differences on the externalizing or learning scales of the CPRS-48. Discriminant function analysis using preselected PIC variables yielded a correct group classification of 92.7%. The PIC appears to be a useful tool in the differential diagnosis between PDD--NOS and ADD, while the CPRS-48, a commonly used screening measure for attentional and behavioral disorders, does not.