What if we have too many models of worry and GAD?

It is now almost 40 years since Borkovec and colleagues provided this definition in their seminal paper and so launched the modern psychological study of worry, and by extension generalized anxiety disorder (GAD). Their classic definition has inspired and guided the developments of models and treatments since, and within this definition we can find some of the differences in emphasis between the models as well as the ongoing debates. These include the role of thoughts versus images, the function of worry, the role of affect or emotion, the degree to which worry is controllable, the role of uncertainty, and how worry may relate to fear. Interestingly, this definition appeared in 1983, soon after the arrival of GAD as a diagnostic category in the third edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III; American Psychiatric Association, 1980), following the decision to split the DSM-II (American Psychiatric Association, 1968) category of anxiety neurosis into GAD and panic disorder (see Crocq, 2022, for a historical overview). However, worry as a defining feature did not arrive until DSM-III-R (American Psychiatric Association, 1987). DSM-IV (American Psychiatric Association, 1994) reduced the list of associated symptoms, and the definition of GAD was relatively unaffected by DSM-5 (American Psychiatric Association, 2013). Therefore, we have had a reasonably stable definition of GAD with worry as a defining feature for almost 30 years, and now the 11th edition of the International Statistical Classification of Diseases and Related Health Problems (ICD-11; World Health Organization, 2022) broadly aligns with DSM-5. Despite definitional and diagnostic stability, our understanding of GAD in psychological terms is far from stable.