I don't know if I agree with this, though:
> [T]hese people are suffering terribly, in dire need of help, and when we expend our resources chasing new diagnoses (in the absence of good reason to believe there's a new illness), we're "validating" them at the expense of actually helping them.
Was trying out nasal implants on ENS patients "validating them at the expense of actually helping them"? Because the implants apparently turned out to help in many cases.
And: what constitutes good reason to believe there's a new illness? That's a hard question, which I'm sure can and will be debated forever. But I think that the condition turning out to respond to a novel treatment -- like nasal implants, in this case -- has to be considered some degree of evidence that there's a novel illness.
Can you see the difference between the two?
The first I would paraphrase as: "The patient refuses to accept that his condition is psychological, and we do him a disservice by validating the idea that it might not be."
The second I would paraphrase as: "While there is always the possibility that this is a new condition we don't yet understand, statistically speaking it is far more likely to be psychological. Given finite resources, diagnosis and treatment for depression/anxiety is by far the best bet for giving the patient real relief."
To me the certainty of exclusion in the first message just immediately sets off alarm bells.
"This person has X" most of the time means "X has a strong statistical advantage in explaining this patient's symptoms, so we're going to pursue treatment for X until accruing evidence suggests we shouldn't." I guess that's not always true, given a few things that exist by definition, but it's mostly true.
And that's generally good enough, since... well, statistical masses tend to obey statistical properties.
My mistake.
> You seem to be claiming that it's settled.
No. There are doubtless many rare variants of human ailment we haven't understood or discovered yet. Literally, you could come up with at least one ailment for every enzyme and cell-surface molecule on the human body, at least.
My issue is that every few years there comes up a new anxiety/depression fad: some subset of folks with anxiety and depression with attribute it to some new undiagnosed condition (almost always musculoskeletal), and whip up a frenzy.
Is it possible that there are these large numbers of usually-musculoskeletal rare disease variants that all happen to look like anxiety and depression?
Well, yes, there could be. But considering how woefully under-diagnosed and under-treated mental health is in this country, and that between anxiety disorder and MDD you have a twelve-month prevalence in the US of >20%, you are far, far, far more likely finding people with anxiety/depression and a dollop of either denial or misunderstanding[1].
All of medicine comes down to the Bayesian discipline of figuring out what the most likely cause of an issue is, and collecting evidence to support/disprove that until it's no longer the most likely cause, or until the ordering stops changing. That's it. Jumping down the list is medically irresponsible. Every treatment, at that point, is unethical: you can't justify cost vs. benefit of treatment benefits and side-effects when there's every likelihood the patient doesn't have that rare thing.
So, before inventing new diseases every handful of years, we need to stop and say "is there any good evidence that this is a 1/1,000,000 new illness, vs. the anxiety/depression for which there's a >20% chance it is?" In this case, the sum total of evidence for novel disease amounts to the possibility of "possible injury to nasal sensory neurons creates a little numbness in the nose; subject of anxious obsession by pts w/ anxiety."
I don't argue this because it amuses me to say "no, silly rabbit, you're not allowed to have your own new disease." It's because these people are suffering terribly, in dire need of help, and when we expend our resources chasing new diagnoses (in the absence of good reason to believe there's a new illness), we're "validating" them at the expense of actually helping them.
[1](Yes, patients with anxiety can just genuinely not understand they have it. Anxiety can come on as strictly somatic symptoms, and the common layperson can rationally say "I don't feel anxious or panicked at all; I'm just having trouble breathing. Non-sense!" It's a poorly named disease.)