Phenomenology and course of generalised anxiety disorder

The diagnostic category of generalised anxiety disorder (GAD) was originally intended to describe residual anxiety states. Over the years clinical criteria have been refined in an attempt to describe a unique diagnostic entity. Given these changes, little is known about the clinical course of this newly defined disorder. This study investigates the longitudinal course, including remission and relapse rates, for patients with DSM-III-R defined GAD.

Analysis of the 164 patients with GAD participating in the Harvard Anxiety Research Program. Patients were assessed with a structured clinical interview at intake and re-examined at six month intervals for two years and then annually for one to two years. Psychiatric Status Ratings were assigned at each interview point. Kaplan-Meier curves were constructed to assess likelihood of remission.

Comorbidity was high, with panic disorder and social phobia as the most frequently found comorbid disorders. The likelihood of remission was 0.15 after one year and 0.25 after two years. The probability of becoming asymptomatic from all psychiatric symptoms was only 0.08.

This prospective study confirms the chronicity associated with GAD and extends this finding to define the one and two year remission rates for the disorder. Likelihood of remission for GAD and any other comorbid condition after one year was half the annual remission rate for GAD alone.