The narrative that the psychiatrists are trying to write is a triumphal progression from anecdote to empiricism, from Freud's couch to the colorful images of the fMRI.
Unfortunately, the example psychiatrists would like to follow, medicine, is not as simple as all that. When we diagnose, we often apply a heuristic which relies not just on results of tests and images but also on the patients' symptomatic report. Call it "bacterial pneumonia" all you want, but a patient without symptoms can't be diagnosed with pneumonia even if there's an infiltrate on the X-ray. And even if a patient is symptomatic, we don't go and culture the bacteria from the lung tissue except in relatively serious circumstances.
The point here is not the details of what makes a pneumonia, merely that we do not have a magic on-off switch within the body that we can examine when making a diagnosis. Psychiatrists know this as much as we do, which is why (to internists' secret shame) we don't have anything like a unified diagnostic and statistical manual, and if we did, it would be just as controversial as the DSM.
Zackary Berger, MD, ACP Member, is a primary care doctor and general internist in the Division of General Internal Medicine at Johns Hopkins. His research interests include doctor-patient communication, bioethics, and systematic reviews. He is also a poet, journalist and translator in Yiddish and English. This post originally appeared at his blog.
