This doesn't address in any way the point being made about false positives leading to overly high estimates of prevalence in the general population, whereas nullc's comment is probably quite close to explaining the issue.
> This doesn't address in any way the point being made about false positives leading to overly high estimates of prevalence in the general population
It does if you are aware of the fact that these tests are never used on its own to diagnose depression/anxiety.
The GP or psychologist determines if the client exhibits symptoms of depression, and THEN performs the test, often in combination with other tests that test similar things. Afterwards the results of those tests (as well as the dialogue that's been had with the client), are used in conjunction to determine if a diagnosis is appropriate.
I think it's rather arrogant to assume that psychologists/diagnosticians/statisticians are oblivious to the fact that tests have reliability/validity measures. Of course they are aware, that's their job.
