The long-term course of anxiety disorders : An epidemiological perspective

Anxiety disorders are very common and impose a considerable burden for patients, relatives, and society. There are several anxiety disorders, all of which are known for their often persistent course. Nevertheless, there is a lack of knowledge about its longitudinal course trajectories, which hampers prevention strategies and adjustment of treatments according to prognosis. The aim of this thesis was to get more insight into the longitudinal multi-year naturalistic course of anxiety disorders and to identify the factors that are associated with this course.

The research of this thesis has shown that diagnoses of anxiety disorders can change over the years and are not very consistent. In addition, it was found that certain psychological characteristics, in particular anxiety sensitivity (tendency to view anxiety symptoms as harmful) and locus of control (degree to which people believe they can control the events that influence their lives), are related to course trajectories of anxiety. Another factor studied, namely personal preference for time of sleep and activity (also called chronotype), was not related to the course. It was further found that psychological and clinical characteristics (e.g. panic attacks, comorbid personality disorders, and avoidance) predict persistent anxiety disorders, whereas sociodemographic characteristics (e.g. level of education and socioeconomic status), although predictive of anxiety disorder onset, did not predict anxiety disorder persistence. These predictors could potentially identify patients at risk of an unfavorable course and could offer them more targeted or more intensive treatment at an early stage.