Comparing Rates of Diagnosis Using DSM-IV-TR Versus DSM-5 Criteria for Autism Spectrum Disorder.

Jason and his team looked at babies and toddlers who were being checked for autism. They asked: does the newer DSM-5 rule book catch the same kids as the older DSM-IV-TR?

They scored each child with both sets of rules and counted how many got an ASD label each way.

DSM-5 gave fewer ASD diagnoses than the old rules. Kids with lots of clear signs usually met both sets. Children with milder or fewer symptoms were the ones most often dropped under DSM-5.

Edgin et al. (2017) saw the same age group while DSM-IV-TR was still in use. They found kids were already getting milder labels over time. Jason’s 2020 study shows one reason: the newer DSM-5 simply sets a higher bar.

Flapper et al. (2013) showed that even at 18 months, toddler symptoms line up with the three classic autism factors. Jason’s work adds that DSM-5 keeps those factors but demands more evidence before giving the diagnosis.

Peters et al. (2013) linked maternal smoking to the broad PDD-NOS label under DSM-IV. Jason warns that such borderline cases may now be missed entirely under DSM-5.

If you assess toddlers for ASD, expect a small drop in diagnoses after you switch to DSM-5. Plan extra data—video, parent interview, repeated observations—before you tell a family their child doesn’t qualify. Re-check kids who just miss the cut; they may need services later.