Two-year course trajectories of anxiety disorders: do DSM classifications matter?

OBJECTIVE

Anxiety disorders have been shown to differ in their course, but it is unknown whether DSM-categories represent clinically relevant course trajectories. We aim to identify anxiety course trajectories using a data-driven method and to examine whether these course trajectories correspond to DSM-categories or whether other clinical indicators better differentiate them.

METHOD

907 patients with panic disorder with agoraphobia, panic disorder without agoraphobia , agoraphobia, social phobia, or generalized anxiety disorder according to DSM-IV criteria were derived from a prospective cohort study (Netherlands Study of Depression and Anxiety). Baseline data were collected between September 2004 and February 2007; follow-up data, between October 2006 and March 2009. Latent class growth analysis was conducted, based on symptoms of anxiety and avoidance assessed with the Life Chart Interview covering a 2-year time period. Identified course trajectories were compared with DSM-IV diagnoses and a wider set of predictors.

RESULTS

We identified a class with minimal symptoms over time (41.7%), a moderately severe chronic class (42.8%), and a severe chronic class (15.4%). Panic disorder with agoraphobia (OR = 2.14; 95% CI, 1.48-3.09) and social phobia (OR = 1.97; 95% CI, 1.46-2.68) predicted moderately severe chronicity; panic disorder with agoraphobia (OR = 2.70; 95% CI, 1.66-4.40), social phobia (OR = 2.46; 95% CI, 1.62-3.74), and generalized anxiety disorder (OR = 1.86; 95% CI, 1.23-2.82) predicted a severe chronic course. However, baseline severity, duration of anxiety, and disability better predicted severe chronic course trajectories than DSM-categories. Additionally, partner status, age at onset, childhood trauma, and comorbid depressive disorder predicted chronic courses.

CONCLUSIONS

Course of anxiety was pleomorphic with over 40% having a favorable course, thereby questioning the common notion of chronicity of anxiety disorders. Severity, duration of anxiety, and disability were able to better identify severe chronic course trajectories as compared with DSM-IV categories. These findings facilitate the identification of chronic course trajectories of anxiety disorders in clinical care and support current debates on staging and profiling of mental disorders.