Can PTSD be both over- and underdiagnosed?

When you propose that we are overdiagnosing PTSD in vets, you run into not only a lot of flak but many offerings of evidence suggesting that we're missing a lot of cases. Since publishing my article on PTSD, I've received those arguments directly in comments, and on Wednesday, April 8, Salon published an article, "I am under a lot of pressure to not diagnose PTSD," by Michael de Yoanna and Mark Benjamin, that offers unsettling evidence that at least some doctors working for the VA are being pressed to not diagnose PTSD in combat vets.

So which is it? Are we under- or overdiagnosing PTSD in vets?

As I suggested in the article, and as the blogger Neuroskeptic suggested in a comment on another of my posts, the answer is almost certainly both. I won't repeat the evidence in the article and its supporting materials that we're overdiagnosing PTSD. But what about the evidence we're missing cases?

Two answers. First, as I noted in the article,

The idea that PTSD is overdiagnosed seems to contradict reports of resistance in the military and the VA to recognizing PTSD denials of PTSD diagnoses and disability benefits, military clinicians discharging soldiers instead of treating them, and a disturbing increase in suicides among veterans of the Middle East wars. Yet the two trends are consistent. The VA's PTSD caseload has more than doubled since 2000, mostly because of newly diagnosed Vietnam veterans. The poor and erratic response to current soldiers and recent vets, with some being pulled quickly into PTSD treatments and others discouraged or denied, may be the panicked stumbling of an overloaded system.

Keep in mind that the VA is a huge, sprawling organization -- the biggest single part of the government -- and that different VA facilities can behave quite differently from one another, with some tending to overdiagnose and perhaps others not so much.

The military, meanwhile -- meaning the Army, Navy, Marines, and Air Force -- is driven by different criteria, policies, concerns, and cultures. Overall -- though this varies a lot by base, region, and even unit -- the military appears less friendly to giving PTSD diagnoses. The soldier on active duty has more to lose from a PTSD diagnosis than does a vet, and so is less likely to seek it (or other mental health help), and there are many reports of both the general culture and specific policies (de facto or official) discouraging recognition of PTSD or other forms of mental distress. And the military is under great strain from its overextension in Iraq and Afghanistan. So you have many soldiers under tremendous mental and psychological pressure even as the military is desperately trying to retain them.

That would account for the sort of resistance to PTSD diagnoses documented in the Salon article.

It's a deeply troubling article. But it doesn't prove we aren't overdiagnosing PTSD. It is perfectly possible that we can overdiagnose a condition -- that is, mistakenly give diagnoses of Condition A to a lot of people who have something else -- while also missing and failing to treat people who actually have Condition A. If you're mistakenly making 100,000 Condition A diagnoses while missing 50,000 genuine Condition A cases, you're still overdiagnosing Condition A, even though you're missing a lot of people who have it. This happens all the time. We overdiagnose heart attacks, for instance -- resulting in the deaths of people who have, say, pulmonary thromboses -- while still missing a lot of heart attacks.

It's clear likewise that we are giving PTSD diagnoses to a lot of people who don't have it. It's also clear that we're missing some genuine cases -- partly because patients don't necessarily come forward, but also because the PTSD treatment system is so overwhelmed by overdianosis of PTSD that in some places it's pushing back. But the driver behindn this mess is the overdiagnosis of PTSD and the dysfunctional health-care access and disability-benefits structures that help encourage it. If the VA, the DOD, and the APA can clean up the PTSD diagnosis and remove the perverse access and disabilty-benefit structures, it'd be a lot easier to properly treat all vets for what truly ails them, rather than what bureaucratic structures and cultural forces seem to prefer.

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I don't think very many clinicians would be surprised to hear that PTSD is both overdiagnosed and underdiagnosed. Probably the same is true for many diagnoses. This phenomenon has been demonstrated for ADHD, for example.

There are two points to keep in mind. For one, you will hear people say that this misdiagnosis is a problem because there is no "blood test" for PTSD. This much is true: there is no objective biochemical assay.

However, if you look into the correlation between the clinical cause of death that is declared at the time of the death of a patient, and the actual cause of death as determined at autopsy, you will see that there is plenty of misdiagnosis even for conditions for which there is a biochemical assay or other objective test. So that is a bogus argument.

Second, if there is a problem with the disability determination process, that is a separate issue from the problems that may occur with overdiagnosis. There is not particular reason why the formal diagnosis should have anything to do with the determination of disability.

All DSM diagnoses, including PTSD, were developed for clinical and research purposes. In the development of DSM diagnoses, there is no research -- indeed, no effort of any kind -- to validate the diagnoses as markers of disability. None. They do not and should not have anything to do with each other.

There are many persons with PTSD who continue to work for a living. There are plenty of people who have some of the features of PTSD, but who do not meet all the criteria, who are not able to work. Sure, there probably is a correlation, but it is not particularly close to 1. The diagnosis is a valuable and powerful tool, but you have to use the right tool for the job at hand. If the job is to determine disability, it is the wrong tool.

Even when it comes to treatment planning, the diagnosis is only advisory. There is no 1:1 mapping between diagnosis and treatment. There are plenty of persons who do not meet full formal criteria for PTSD, who still can benefit from the same kinds of treatment that would be provided for someone who does meet the full criteria. Likewise, there are people who do meet the full criteria, but who might do best with some other kind of treatment.