> Over-diagnosis is only an issue in cases where prevalence is below the false positive rate (technical term is "sensitivity") of the test. That is not the case here.
The term "overdiagnosis" is actually ambiguous. As [1] points out, the word is used in two different ways: (a) to argue that the diagnostic criteria (such as in the DSM-5) are overly broad, and are labelling people as having a "disorder" who shouldn't be so labelled ("pathologising of normal human experience"); (b) to argue that the diagnostic criteria are being systematically over-applied, where people who don't actually meet the formal diagnostic criteria are nonetheless frequently being given the diagnosis.
This is a fair point. I read the op's comment as using the former definition. The latter definition wouldn't really apply as this is being determined by standardized testing. Unless one thinks that the standardized tests are overly liberal (their criteria are based on correlations with in-person diagnoses, so it's possible).
Well, it is a legitimate question of how well the standardised tests actually fit the diagnostic criteria for various disorders. [1] argues that the fit between the commonly used standardised tests for ASD and the DSM-5 diagnostic criteria is less than ideal. (And I doubt this finding is unique to ASD, I think it likely if you repeated the authors' exercise for other diagnoses you would get similar results.)
The term "overdiagnosis" is actually ambiguous. As [1] points out, the word is used in two different ways: (a) to argue that the diagnostic criteria (such as in the DSM-5) are overly broad, and are labelling people as having a "disorder" who shouldn't be so labelled ("pathologising of normal human experience"); (b) to argue that the diagnostic criteria are being systematically over-applied, where people who don't actually meet the formal diagnostic criteria are nonetheless frequently being given the diagnosis.
[1] https://aifs.gov.au/cfca/publications/diagnosis-child-mental...