The validity of autistic spectrum disorders: a literature review.

Szatmari (1992) read every paper on autism subtypes. The goal was to see if Asperger, low-IQ, and high-IQ groups are truly different.

The review looked for proof that each group has its own cause, course, or treatment need.

The paper says we can tell the three groups apart at the clinic. Yet it found only weak hints that the groups differ in cause or outcome.

In short, the labels exist, but science had not proven they matter for treatment.

Ekas et al. (2011) later tested the same idea with real data. Once age and IQ were matched, PDD-NOS and classic autism looked almost the same on parent reports. This direct finding clashes with the 1992 claim that subtypes stand out.

Woodbury-Smith et al. (2005) gave the idea partial support. Two-thirds of kids given an Asperger label still kept it under newer DSM rules, so the label held some weight.

Rutter (2013) closed the loop. That review said the field must drop old boxes and rethink autism from the ground up, moving past the 1992 view.

For you at the clinic table, the takeaway is caution. Use Asperger or PDD-NOS labels for description, not for picking unique treatments. Treat the child, not the subtype. Keep watching new evidence, because the story keeps changing.