Evolutionary foundations for psychiatric diagnosis: making

The third and fourth editions of the Diagnostic and Statistical Manual of Mental Disorders (DSM) have brought much-needed reliability to psychiatric diagnosis. However, as is often the case, progress comes at a price. In this chapter, we support Wakefield's argument that DSM-111 and DSM-IV typically ignore one of the most fundamental distinctions in medicinethe distinction between symptoms and the situations or diseases that cause them. In the case of emotional disorders, such as mood and anxiety disorders, this mistake is particularly deplorable, because many emotions are responses that evolved because they are protective in untoward circumstances. Here we suggest that an evolutionary perspective can advance the nosology of emotional disorders in several ways. First, this perspective confirms that the normality of an emotion depends necessarily on the context. Furthermore, it notes that variations in brain mechanisms that make a person susceptible to anxiety or depression are only sometimes diseases; more often they may have the same causal significance as variations in brain mechanisms that make a person especially prone to cough or fever during a cold. An evolutionary perspective also indicates that biologically normal responses may be aversive and even harmful to individuals. Finally, it suggests the importance of a detailed and evolutionarily informed analysis of the motivational structure of every patient's life.