On depression
Now, to be fair, Dr. Cruise's position is more that depression may be real, but should be treated "naturally" rather than chemically or through mental therapy. Also to be fair, it is nearly impossible to establish objectively what is going on in anyone's head.
I have suffered from occasional depression, sporadically, for years. It manifests as a lack of motivation and a tendency to snap at people, but it does not really keep me from functioning, so it is not classified as a treatable disorder in my case. It is just that everything seems to irritate me, nothing seems fun, and I do not even enjoy the taste of my favorite foods. Traditionally, I just go through the motions for a few days until it passes.
Dr. Cruise, known for such scholarly works as "Risky Business," could contend that I was just cranky and sandbagging. And it would be difficult to prove otherwise, objectively, without a thorough internal examination of my brain and its chemistry. Most everything we know about the brain, we know by inference, because we cannot physically test one in a live subject without serious limitations. ("A little to the left--and try not to paralyze this one, Herr Docktor.")
Nevertheless, inference is a powerful tool, and, based on my memory of various psychology classes I took 15 years ago, we do know these things: The brain is a complex chemical system unmatched in nature or laboratory. All actions and reactions are the result of chemical signals, and some inactions are the result of an absence of chemicals. Add in some personal experience (about which I am competent to testify), and it makes for a convincing case.
But getting back to the argument, let's put aside "delusion," on the theory that substituting the name of one mental illness for another is not productive. That leaves attention-seeking as an explanation for claims of depression--which is illogical in most cases. For example, Munchausen's Syndrome does cause real physical ailments, but that does not mean that most (or even a large percentage of) individuals visiting physicians are just seeking attention.
So, despite Mr. Cruise's credentials, I cannot dismiss psychiatry in general or depression in particular as fakery.