Every day there’s a “something correlates with autism” story; Emily Willingham just did a roundup of weird ones. When I first started to learn about autism, it took no time to realize that these aren’t very helpful. I wish researchers would focus elsewhere, and some already are.

Here are two studies (these happened to pop up today) that did better:

• Social skills and motor skills are correlated
• de novo mutations are elevated only when autism accompanies intellectual disability

I didn’t dig in on these studies in detail, the point is that their reported findings are much more informative than they would be if they were simply “autism correlated with motor skill impairments” or “autism correlated with de novo mutations.” They go a level deeper and attempt to look at dimensions within autism.

Here’s what’s wrong with a “correlate autism with X” study.

Plenty of evidence seems to support the idea that autism is more like a trait or symptom than a disease. Some people seem to experience autism primarily as sensory differences; others as a different kind of thinking (perhaps in pictures, or in explicit, intellectualized fashion); others emphasize medical issues such as seizures or tuberous sclerosis with autism as an effect. Sometimes autism comes with intellectual disability, other times it doesn’t. It may or may not imply motor deficits. On and on — there are so many differences. We’ve put all kinds of people and experiences together and said: these people have a brain focused on something besides social interaction, and that’s what’s most important about them.

We need to view this grouping as contingent and pragmatic, to be used when it makes sense. If we’re asking, “should we be concerned about this person’s ability to make friends and navigate social situations in daily life?” then the broad “autism” label is appropriate, because it’s defined by something close to that question.

But if we’re asking, “what specific education or accommodation does this person need?” or “what strengths might this person have to build on?” or “do we expect problems other than the core social deficits?” or “what causes autism?” … any practical question, really … we need more specific ways to group and understand people. Just “autism” tells us little, and may even be actively misleading.

“Autism” has a crude yes-or-no quality. If someone is just outside the autism range on the usual autism assessments, are their social skills perfect or might they benefit from extra help in those areas?

What could researchers do to improve?

1. Measure autism dimensionally … continuing those measures outside the official spectrum. See if the variable you’re looking at also relates to more-autism-like but not-quite-diagnosable “neurotypicals,” for example.
2. Measure separate aspects of autism separately. Some research suggests that sensory issues and social issues may not be strongly related, for example.
3. Look for relationships among those variables which aren’t part of the autism diagnosis, but crop up often in autistic persons. Motor skills differences; language differences; picture-thinkers and word-fact thinkers; attention-seeking behavior; verbal vs. non-verbal; presence of medical issues such as seizures.
4. Some studies have tried to find commonality in “responders” and “non-responders” to intervention; those are great studies! Which people benefit from which kinds of help?

“Autism correlates with X” research really falls over when it comes to debates about the DSM criteria. How are we supposed to improve the criteria by finding things that correlate with the current criteria? Circular and nonsensical.

In the end, a yes-or-no on autism isn’t enough.  We need to describe a person more specifically, including their strengths, and then list social deficits or repetitive behaviors as one aspect of whatever’s going on with that person. Once we understand autism, it probably goes away as a diagnosis and returns as a trait (one associated with certain diseases, perhaps, but perhaps also arising from certain strengths).

There’s plenty of anecdata out there about kinds of people with autism; picture-thinkers, “little professors,” memorization-loving hyperlexics, lovers of sensory experience. It’s time to try understanding these differences in earnest.

Take the study I linked to earlier, reporting that de novo mutations only correlate with autism with intellectual disability? If that turns out to be true, does it mean that some autisms with and without intellectual disability have distinct causes? It’s a fascinating clue.