Abstract
Despite widespread recognition that psychiatry would be better served by a classificatory system based on etiology rather than mere description, it goes without saying that much of the necessary work is yet to be done. In this chapter I take up the increasingly important question of how mechanistic explanation fits into the larger effort to build a scientifically sound etiological and nosological framework. I sketch a rough picture of what mechanistic explanation should look like in the context of psychiatric research, with a focus on several potential challenges posed by the special features of many psychiatric conditions. These include the role of social and environmental factors, the relatively transient nature of symptoms, the presumably complex organization of underlying systems, and the likelihood that many disorders are the product of nonstandard development. I suggest that these explanatory challenges can be met with a sufficiently broad notion of mechanism, one that allows for something less than the flawless execution of internal operations, appeals to the influence of contextual factors, and attends to organizational relations both within the mechanism itself and across the wider cognitive system.