Michael Fisher of UCSF recently published an interesting account of various stakeholders' views on the prevalence of posttraumatic stress disorder. In the paper, published in the forthcoming issue of Social Science and Medicine, he notes that depending on a given official's position, she may consider PTSD to be over- or under-diagnosed. Fisher discusses the implications of the perceptual imbalance with respect to stigmatization and advocacy. The article is appropriately titled "PTSD in the U.S. Military, and the politics of prevalence."

But there's a bit of 'so what?' at play here. To me, we're left wondering about the tangible important of prevalence. Certainly, the figure plays into science and research funding, as prevalence is useful in allocating money insofar as it is helpful in quantifying the global or national burden of a given disease. But are the differences between perceived "over-diagnosis" and "under-diagnosis" enough to actually warrant a change in global burden relative to other disorders?

Of course, a true interrogation of that question leaves us confronting the politics of the politics of prevalence.