Two thoughts on this. Note that I'm not explicitly disagreeing to you, just responding. (1) No blood marker, no brain scan, true. But, it's something that do

Two thoughts on this. Note that I'm not explicitly disagreeing to you, just responding. (1) No blood marker, no brain scan, true. But, it's something that does become evident in people later, so the test has later symptoms that it can be checked against for its error rate. (2) It could be "hysteria", but it's still people acting unusually (at least later in life). Perhaps it's something that's changed in the way we raise our kids, or environmental, or changes in prenatal/birth-giving/etc practice. Any way, it's a change in our population and is interesting enough to follow.