In this final chapter, we tie up several loose ends of our argument. First, we consider the question: If the flaws in current diagnostic criteria are as compellingly clear as we argue that they are, then why haven+U0027t they been changed, or why can+U0027t they easily be changed? In addressing this question, we shift from the logic of diagnosis to the logic of powerful constituencies and vested interests that come into existence once a definition of disorder is in place. Second, we return to the evolutionary perspective on disorder that we presented in the first two chapters and that serves as the framework for much of our argument. The scholarly literature has posed many objections to this view. We review some of the most interesting objections and briefly explain why we think none of them places the evolutionary understanding of normal human functioning in doubt. Finally, this book is mainly an analysis and critique. However, many readers will be wondering what the solution to the problems we identify might be. So we offer some initial thoughts on strategies by which the approach to diagnosis of MDD might be changed to be more valid.
We have argued that there is an obvious logical problem with the current DSM definition of Major Depressive Disorder. We have documented how this problem has radiated throughout the mental health treatment and research establishment, as well as into the realm of public policy, to expand the domain of depressive disorder. Yet the definition is resilient; it has survived three revisions of the DSM, and there are few signs to suggest that changes in the MDD criteria are a high priority for the next revision, DSM-V. Assuming that our argument has merit, it seems reasonable to ask: What stands in the way of simply changing this definition and correcting a logical gap?
All else being equal, there are legitimate reasons for being conservative about changing diagnostic criteria. Perhaps the major one is that studies that use