A week or so ago the NY Times, Newsday, and I think the NY Daily News (and probably every other paper) all featured stories about a study that showed that more than 1 in 2 Americans had some sort of mental illness. I didn't read any of the articles all the way through (or try to find the study itself online) for lack of time and I failed to blog it for the same reason. Obviously, the headlines and lead paragraphs for these stories weren't enough to figure out what was wrong the study but if I think of all the people I know, I'm pretty sure not every other one is mentally ill.
Somewhere, there's an alternate universe where I have time to blog and the ability to righteously fisk studies like this, but it ain't this one.
Thankfully, The Weekly Standard can find people to do just that. I knew something was wrong with the finding and this article does a good job at explaining the study's flaws.
In addition to relying solely on respondents' yes or no answers to a checklist, the investigators are committed to employing the official Diagnostic and Statistical Manual of Mental Disorders--Fourth Edition (abbreviated DSM-IV), which bases all psychiatric diagnoses on symptoms and their course, not on any fuller knowledge of the person. It is as if public health investigators studying the prevalence of pneumonia over time in the American population were satisfied to call every instance of a cough with a fever and a mucoid sputum a case of pneumonia.
Internal medicine gave up on symptom-based diagnosis more than a hundred years ago, replacing it with diagnosis that rests on knowledge of pathology and what produces it. Thus, internists no longer speak of coughs as racking, brassy, or productive, but as produced by viral or bacterial infection, allergies, or vascular congestion. They no longer differentiate Tertian, Quotidian, and Continuous Fevers but fevers from infection, neoplasia, dehydration, and so on.
