Clinical epidemiology of commonly occurring anxiety disorders : insights into the phenomenology and course of anxiety disorders from the Leiden Routine Outcome Monitoring Study

Anxiety disorders as a group are the most prevalent psychiatric disorders. Although they have been studied extensively, previous research has focussed primarily on members of the general population, or on participants in clinical trials. As both groups may differ substantially from patients who are seen in clinical practice, it is unclear to what extent previous findings can be generalised to a clinical setting. In order to gain insight in the clinical epidemiology of anxiety, it is necessary to study outpatients. This thesis describes several studies in which naturalistic data, collected through Routine Outcome Monitoring, were used. Chapter two describes the age of onset of panic disorder, agoraphobia, social phobia and generalised anxiety disorder. Chapter three explores age related differences. In chapter four predictors of treatment response are identified and the fifth chapter describes patient characteristics that are associated with the course of suicidal ideation in anxiety and depression. In chapter seven a self-report measure of anxiety severity is compared with an observer rated measure and patient characteristics associated with discrepancies between both measures are identified. In the final chapter findings are discussed and recommendations for future research are made.