Identifying and Differentiating PDD-NOS: A Comparison with Autism and ADHD

Abstract

Identifying and Differentiating PDD-NOS: A Comparison with Autism and ADHD Purpose: We aimed to investigate differential features of pervasive developmental disorder- not otherwise specified (PDD-NOS) in terms of presenting symptoms, developmental history, and comorbidity with respect to autism and attention deficit hyperactivity disorder (ADHD). Method: The study involved 188 children (PDD-NOS n=94; ADHD n=47; autism n=47) (male n=150, female n=38) who were 5.5(±2.5) years old on average (range 2-11 yrs.). Preliminary PDD-NOS screening scale (PPSSS) was developed based on the 'presenting' symptoms of PDD-NOS that were systematically collected in a pilot group of children. The clinical diagnoses and comorbidities were based on the comprehensive mental status examination, Schedule for Affective Disorders and Schizophrenia for School Age Children-Present and Lifetime Version-Turkish Version (K-SADS-PL-T), and the consensus between two child and adolescent psychiatry specialists. Results: The prevalence rates of the most common presenting symptoms in the PDD-NOS and autism groups have shown a similar pattern of distribution from most common to the least, even when the results were corrected for age. However, almost all of these symptoms are reported significantly less in prevalence in the PDD-NOS group. Using subjects in all diagnostic groups (n=188), a principal axis factor analysis with Promax rotation revealed ten factors; seven were found to be discriminative. In addition, another factor analysis revealed three factors: (1) "autism spectrum,"(2) "disruptive behaviors spectrum," and (3) "anxiety spectrum." The first two factors were found to discriminate between the diagnostic groups. Discussion and Conclusion: The results suggest that PDD-NOS may be assumed as a quantitative partial subtype of autism, and it represents a less severe form that lies on a continuum of social-communication skills.