At what age can children with pervasive developmental disorder not otherwise specified be distinguished from children with autism based on specific criteria?

• A. One year of age
• B. Two years of age
• C. Three years of age
• D. Four years of age

Answer: (B)

The age of two years is significant because by this time, children can exhibit a range of social, communicative, and behavioral traits that are essential for distinguishing between pervasive developmental disorder not otherwise specified (PDD-NOS) and autism spectrum disorder (ASD).

At two years, developmental milestones become more apparent and observable. For instance, children with autism may display more evident signs of social impairment, restricted interests, and repetitive behaviors at this age, while those with PDD-NOS may show atypical development but not to the same degree or specific type as seen in classical autism.

The diagnostic criteria provided in tools such as the DSM-5 enable clinicians to assess developmental patterns and behaviors more effectively around this age, leading to clearer differentiation between the disorders. Thus, the age of two becomes a critical time when signs can be assessed and categorized, aligning with clinical practice guiding early diagnosis and intervention.