> Historically no test existed other than behavior observations. Oh look a cluster of behaviors, we'll call it a disease.

What medical literature calls it a disease? I've only ever heard it called a disorder. Why wouldn't they classify a bunch of behaviors under the same umbrella? They've gotten better and better at subdividing the class of disorders. I'm not sure i understand the problem with grouping related disorders together.

> That leads to some severe cultural problems like just medicating the hell out of people until their vegetate. Not a very nice thing to do.

You can't blame cultural issues on the way medicine groups disorders. This isn't One Flew Over the Coo-coos Nest.

> someone needs to be forcibly "fixed" is open to quite a bit of opinion.

Jesus Christ! Some sympathy for parents and caregivers. You act like they don't want what is best for their children.

> OP is correct in that they selected a group of very high functioning people and controls, so what if anything that would have to do with low functioning people is mysterious and its quite possible they have little in common other than symptoms / behaviors.

I'm not sure what you want. You don't like them grouping based on observable behaviors, but you are negative at them trying to find markers through fMRI. If anything, if it works on high functioning patients who have less noticeable behaviors, it is more likely to work on low functioning patients as long as they can understand the tasks. The difference in brain activity should be greater in low-functioning patients (although the algorithm needs to be trained on that set of data).

> So saying "we can detect autism" is kind of like saying "we can fix broken computers". Well, define broken computers narrowly enough and ...

It's the opposite of that. They've proved finding differences in high functioning "computers" so it should follow that finding differences in low functioning "computers" is easier (if you can find a way to get cooperation).

> It does not appear to be a magic bullet along the lines of a glucose tolerance test being pretty effective at diagnosing diabetes.

There was only 34 individuals in the experiment. It needs a tremendous amount of further testing. From the article:

"Despite the very high sensitivity and specificity of the approach (33/34 or 97% of participants classified correctly), the study has clear limitations. First, the current paradigm, requiring significant cooperation during thoughts about social interactions, would be difficult to apply to participants with lower-functioning autism. Second, it is not yet known whether this type of classification can differentiate autism from other special populations, such as those with other developmental and neurological disorders. Furthermore, it would be desirable to develop a neurosemantic screening battery that contains a variety of items capable of evoking altered representations in a number of psychiatric disorders, along with a classifier that accurately identifies the disorder of individual participants. Each disorder could then be identified or diagnosed on the basis of its own characteristic alterations of thought. Because of the many co-morbidities among psychiatric disorders, one might expect classification of some individuals into more than one category. Fortunately, these limitations have the potential of being overcome through further research efforts."