Is pervasive developmental disorder not otherwise specified less stable than autistic disorder? A meta-analysis

Area of Science:

• Neuroscience
• Developmental Psychology
• Psychiatry

Background:

• Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS) is a diagnostic category within autism spectrum disorders.
• Understanding the diagnostic stability of PDD-NOS is crucial for accurate early intervention and long-term prognosis.
• Previous research has indicated variability in the diagnostic stability of PDD-NOS.

Purpose of the Study:

• To systematically review and analyze the diagnostic stability of PDD-NOS.
• To compare the diagnostic stability of PDD-NOS with Autistic Disorder (AD).
• To explore the developmental trajectories associated with PDD-NOS diagnoses.

Main Methods:

• A Medline search was conducted to identify studies assessing the diagnostic stability of PDD-NOS.
• Eight studies were included in the review, with a pooled sample of 322 Autistic Disorder (AD) and 122 PDD-NOS cases.
• Diagnostic stability was assessed using the percentage of individuals with the same diagnosis at two time points; Relative Risk was calculated.

Main Results:

• The pooled Relative Risk indicated significantly higher diagnostic stability for AD compared to PDD-NOS (p < 0.001).
• For PDD-NOS diagnosed before 36 months, the 3-year stability rate was 35%.
• Analysis of developmental trajectories revealed that PDD-NOS encompasses heterogeneous conditions, including prodromal AD, milder forms of AD, and communication/interaction delays.

Conclusions:

• The diagnostic stability of PDD-NOS is lower than that of Autistic Disorder.
• PDD-NOS is a heterogeneous category that may represent different developmental pathways, including early or less severe forms of AD.
• Further research is needed to refine diagnostic criteria and understand the long-term outcomes for individuals diagnosed with PDD-NOS.