Abstract
Objective: This paper aims to describe some of the challenges in psychiatric classification, using generalized anxiety disorder (GAD) as an example. A range of different conceptualizations of GAD are presented. Some are based on theoretical formulations, while others draw on epidemiological data. Each has merit, but also deficiencies. The evolution of diagnostic criteria is not simply a theoretical exercise, but reflects assumptions about the nature of the underlying pathology and the relationships between different disorders. Furthermore, these criteria determine which subjects are included in research and in clinical trials, so they shape the further development of psychiatric classification systems.
Conclusion: The controversies about the classification of GAD illustrate the complexities and challenges of developing a valid classification system for psychiatric disorders.