Long-term chamomile (Matricaria chamomilla L.) treatment for generalized anxiety disorder: A randomized clinical trial Journal Article


Authors: Mao, J. J.; Xie, S. X.; Keefe, J. R.; Soeller, I.; Li, Q. S.; Amsterdam, J. D.
Article Title: Long-term chamomile (Matricaria chamomilla L.) treatment for generalized anxiety disorder: A randomized clinical trial
Abstract: Background Generalized Anxiety Disorder (GAD) is one of the most common anxiety disorders treated in primary care, yet current therapies have limited efficacy and substantial side effects. Purpose To evaluate long-term chamomile (Matricaria chamomilla L.) use for prevention of GAD symptom relapse. Methods Outpatients from primary care practices and local communities with a primary diagnosis of moderate-to-severe GAD were enrolled for this two-phase study at a large US academic medical center. During Phase 1, eligible participants received 12 weeks of open-label therapy with chamomile pharmaceutical grade extract 1500 mg (500 mg capsule 3 times daily). During Phase 2, treatment responders were randomized to either 26 weeks of continuation chamomile therapy or placebo in a double-blinded, placebo-substitution design. The primary outcome was time to relapse during continuation therapy, analyzed using Cox proportional hazards. Secondary outcomes included the proportion who relapsed, treatment-emergent adverse events, and vital sign changes. This study is registered at ClinicalTrials.gov, identifier NCT01072344. Results Between March 1, 2010, and June 30, 2015, we enrolled 179 participants. Of those, 93 (51.9%) were responders and agreed to continue in the double-blind randomized controlled trial. A numerically greater number of placebo-switched (n = 12/47; 25.5%) versus chamomile-continuation (n = 7/46; 15.2%) participants relapsed during follow-up. Mean time to relapse was 11.4 ± 8.4 weeks for chamomile and 6.3 ± 3.9 weeks for placebo. Hazard of relapse was non-significantly lower for chamomile (hazard ratio, 0.52; 95% CI, 0.20–1.33; P = 0.16). During follow-up, chamomile participants maintained significantly lower GAD symptoms than placebo (P = 0.0032), with significant reductions in body weight (P = 0.046) and mean arterial blood pressure (P = 0.0063). Both treatments had similar low adverse event rates. Conclusions Long-term chamomile was safe and significantly reduced moderate-to-severe GAD symptoms, but did not significantly reduce rate of relapse. Our limited sample size and lower than expected rate of placebo group relapse likely contributed to the non-significant primary outcome finding. Possible chamomile superiority over placebo requires further examination in large-scale studies. © 2016 Elsevier GmbH
Keywords: generalized anxiety disorder; clinical trials; herbal medicine; chamomile
Journal Title: Phytomedicine
Volume: 23
Issue: 14
ISSN: 0944-7113
Publisher: Elsevier Gmbh  
Date Published: 2016-12-15
Start Page: 1735
End Page: 1742
Language: English
DOI: 10.1016/j.phymed.2016.10.012
PROVIDER: scopus
PUBMED: 27912875
PMCID: PMC5646235
DOI/URL:
Notes: Article -- Export Date: 6 December 2016 -- Source: Scopus
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  1. Jun J Mao
    244 Mao