I realize, Peter, that that is how psychiatrists, per the DSM or ICD, define the concept of “mental disorder,” and that DPDR meets this universalist definition of “mental disorder.” But this icd definition is so broad and all-encompassing as to include all problems we might suffer from in our lives—as long as that suffering is classified as “clinically significant” (whatever that means). That kind of definition is great if your goal is to claim all of life for medicine, but it’s not necessarily going to help us come to the best understanding, and therefore the best way to deal with, our problems.
Yes, all mental phenomena are dependent, not just on the brain, but on our entire structures. But it does not follow that the mind is reducible to the body. I would agree that I have not seen a mind without a brain, but I’ve also never seen a disembodied brain mind anything. This distinction we have made between mind and body is not empirical, but rather conceptual. Body refers to that aspect of ourselves that is best understood in materialist and mechanistic terms, whereas mind refers to that aspect of ourselves that is best understood in semantic and teleological terms. The foundation of body is matter (structure) while the foundation of mind is not the brain, but language. And language, while also being necessarily contingent on structure, is not reducible to matter.
Of course, this is all a matter of epistemology. If you are a philosophical materialist, then you would have to presume, not that the mind is in or comes from the brain, but that “the mind,” like soul, is an invalid construct. But if that is your position, I would be interested in hearing your explanation of the placebo effect? How is it that when a person ingests a (mostly) inert substance he nevertheless experiences a significant reduction in his suffering? Neuroscience struggles greatly with that one, while semanticists can explain it very convincingly and parsimoniously, in my view. Even though there is no “mind,” it is a valid explanatory concept as distinct from matter.
Im not sure which medical problems you are referring to when you say we found effective treatments before an understanding of its pathophysiology was elucidated. Are you saying that we were able to successfully correct a structural problem before having any understanding of what that structural issue even was? If that’s the case, then we got incredibly lucky. But if you mean that we were able to effectively reduce the suffering of a condition that is defined as a syndrome, of course that happens. In fact, we have been doing that more or less successfully for millennia. Suffering is not the same as derangement of pathophysiology.