Abstract
Anxiety is an adaptive human experience that may occur at all ages and serves to help draw attention to, avoid or cope with immanent threat and danger. Given its evolutionary importance, it has strong genetic and biological underpinnings, and when it serves that adaptive function for the organism, anxiety may be viewed as useful. However, complex adaptive systems, such as our adaptation to threat or stress, by definition provide many and often interrelated points of breakdown or dysregulation, which, if sustained, may lead to psychopathology. Anxiety has been described as a common currency for psychopathology, indicating that it is a first line and universal way for us to respond to stress and threat. It is more or less prominent in patients diagnosed with practically all psychiatric or neurodegenerative disorders. This has lead to the inclusion of anxiety as a cross-cutting symptom measure in the development of DSM-5 (APA, 2013). Given that they are rooted in a complex adaptive system that has many potential points of impact to develop pathology, it is not surprising that anxiety disorders are extremely heterogeneous. This heterogeneity of anxiety disorders pertains to symptomatology, etiology and outcomes, and poses great challenges to both research and clinical practice.
