Treatment of pediatric anxiety disorders: An open-label extension of the research units on pediatric psychopharmacology anxiety study

Background: An 8-week placebo-controlled study, the Research Units on Pediatric Psychopharmacology Anxiety Study, documented beneficial effects of fluvoxamine in the treatment of pediatric social anxiety, separation anxiety, or generalized anxiety disorders. Following completion of this study, participants were invited to enter a 6-month open-label treatment phase designed to examine three issues: (a) long-term maintenance of response in fluvoxamine responders, (b) acute response to fluoxetine in fluvoxamine nonresponders, and (c) acute response to fluvoxamine in placebo nonresponders. Methods: Participants aged 6-17 years meeting criteria for social anxiety, separation anxiety, or generalized anxiety disorders previously treated in an 8-week placebo-controlled trial (n = 128) were offered open treatment. Changes in symptoms of anxiety during open treatment were assessed in three groups: (a) fluvoxamine responders maintained on fluvoxamine, (b) fluvoxamine nonresponders changed to fluoxetine, and (c) placebo nonresponders changed to fluvoxamine. Response was defined based on Clinical Global Impression criteria. Results: During 6 months of continued open treatment, anxiety symptoms remained low in 33 of 35 (94%) subjects who initially responded to fluvoxamine. Among 14 fluvoxamine nonresponders switched to fluoxetine, anxiety symptoms appeared significantly improved in 10 (71%) subjects. Finally, among 48 placebo nonresponders, 27 (56%) showed clinically significant improvement in anxiety on fluvoxamine. Conclusion: The current findings concerning extended treatment of pediatric anxiety disorders are only preliminary, because treatment was uncontrolled. Results suggest that an initial fluvoxamine response is likely to be retained with continued treatment, that some fluvoxamine nonresponders may respond to fluoxetine, and that some placebo nonresponders may respond to fluvoxamine.