This lecture on "diagnostic inflation" or the over-diagnosis or mental disorder by Allen J. Frances, the chair of the DSM-IV task force, is important. Watch it. Frances lays out absolutely staggering levels and rates of change in the recent diagnosis of mental disorder and argues that there is nothing other than diagnostic inflation capable of accounting for it. Rates of diagnosed anxiety disorder, mood disorder, childhood bipolar disorder, autism, ADD and more have boomed in just a few years. Consider ADD. Frances says:
The diagnosis of attention-deficit disorder used to be about 3 - 3 1/2%. Now it's 10%. And 4% of kids in American schools are getting medication. A recent Canadian study really indicates the nature of the problem. It was found that -- and this was a very large number of kids, in Canada -- it was found that one of the strongest predictors of whether you had ADD or not was your birthday. If you were born in December, you are much more likely to have ADD than if you were born in January. The only reason for this could be the school year. That the kids who were younger in the classroom, less mature, instead of being accepted as less mature are being medicalized as having attention-deficit disorder and are all too frequently given medication. A tripling of ADD in just ten years.
The ADD birth lottery example nicely captures how perfectly normal variation -- the fact that slightly younger kids will tend to be less mentally and emotionally developed than slightly older kids -- is now regularly interpreted as evidence of pathology. Frances goes on the explain how very small changes in the diagnostic criteria can lead to an explosion in diagnosis. Even very small proposed but rejected changes can create an inflationary shift in diagnostic norms.
Even if you want to squelch the [tendency toward over-diagnosis in the] system as much as possible, it leaks. Diagnostic inflation is like economic inflation: it's very hard to keep under control; it has many causes; not all of those causes are within your control. The book as written may be very different than the book as used. And once the genie is out of the bottle and the book is published, people can use it their own way, which may be radically different from what you intended.
Frances goes on to explain why he thinks the new DSM-V, focused on prevention, will only make things worse and lead to millions more people being misdiagnosed with mental disorders for perfectly normal and totally healthy psychological conditions. This is a terrific talk stuffed with interesting facts and important insights about the nature of the psychiatric diagnostic system and the incentives at play in the definition of diagnostic categories and the application of these categories to healthy people. Highly recommended, especially if you or someone you care about has been diagnosed with a mental disorder.
If you're interested in these issues, I discuss them further in my Reason review of The Loss of Sadness: How Psychiatry Transformed Normal Sorrow Into Depressive Disorder, by Allan V. Horwitz and Jerome C. Wakefield.