Although I know it's not at all -literally- why they are used (not to mention that they may not work), these tests seem to say something to me about our understanding of depression, right there.
It's kind of hard to ask a rat if he's feeling blue. While I agree that the tests are somewhat suspect, they're used because they provide an objective metric that isn't influenced by experimenter bias. We'll likely need to find something else that will work better.
In the end, I agree with you, but I'll add this: I think this is a triumphant moment for science. We ran tests, we thought we were getting one result, but we got another. Now, we'll reexamine our assumptions, and attack the problem with renewed vigor. The end result will be a much greater, and much better founded knowledge of depression.
I love that science always wins. Even, and especially, when it fails.
