Longitudinal outcome with pharmacotherapy in a naturalistic study of panic disorder

Current recommendations suggest that pharmacotherapy for patients with panic disorder should be continued for at least 1 year [Am. J. Psychiatry 155 (1998) 1], despite a paucity of data systematically examining outcome for periods greater than 3-6 months. It is critically important to obtain more information on the effectiveness of medications over time for patients who initially responded to pharmacotherapy for panic disorder.

Long-term outcome was examined for 78 patients who attained a 2-month period of sustained remission on medication and received maintenance pharmacotherapy for up to 24 months during the Massachusetts General Hospital Longitudinal Study of Panic Disorder, a prospective, naturalistic study. Participants were categorized by their maintenance treatment condition at remission: benzodiazepine alone (N = 45, 58%), antidepressant alone (N = 12, 16%), and combined treatment with a benzodiazepine and an antidepressant (N = 21, 27%).

Approximately half (N = 36, 46%) of the patients who had achieved remission relapsed at some time over the 2-year naturalistic study period, despite continued and adequate pharmacotherapy. There was no difference in timing or frequency of relapse by type of maintenance pharmacotherapy.

Interpretation of the data is limited by the naturalistic nature of the study, and by the relatively low sample size.

This data suggests that patients with panic disorder have a high rate of relapse even after acute response to pharmacotherapy, despite continued treatment. In addition, the use of combined pharmacotherapy with antidepressants and benzodiazepines does not appear to provide greater protection from relapse than monotherapy.