We conducted a randomized, double-blind, placebo-controlled efficacy and tolerability trial of Matricaria recutita (chamomile) extract therapy in patients with mild to moderate generalized anxiety disorder (GAD). We hypothesized that chamomile would be superior to placebo in reducing GAD symptoms with a comparable tolerability profile.
Sixty-one outpatients with mild to moderate GAD were enrolled, and 57 were randomized to either double-blind chamomile extract (n = 28) or placebo therapy (n = 29) for 8 weeks. The study was powered to detect a statistically significant and clinically meaningful group difference in change over time in total Hamilton Anxiety Rating (HAM-A) scores. Secondary outcomes included change in the Beck Anxiety Inventory, Psychological Well Being, and Clinical Global Impression Severity scores and the proportion of patients with 50% reduction or more in baseline HAM-A score.
We observed a significantly greater reduction in mean total HAM-A score during chamomile versus placebo therapy (P = 0.047). Although the study was not powered to identify small to moderate differences in secondary outcomes, we observed a positive change in all secondary outcomes in the same direction as the primary outcome measure. One patient in each treatment group discontinued therapy for adverse events. The proportion of patients experiencing 0, 1, 2, or 3 adverse events or more was not significantly different between groups (P = 0.417).
This is the first controlled clinical trial of chamomile extract for GAD. The results suggest that chamomile may have modest anxiolytic activity in patients with mild to moderate GAD. Future studies are needed to replicate these observations.
From the *Depression Research Unit, Department of Psychiatry, and †Center for Clinical Epidemiology and Biostatistics, School of Medicine, University of Pennsylvania; ‡Investigational Drug Service, University of Pennsylvania Medical Center; and §Department of Family Medicine and Community Health, School of Medicine, University of Pennsylvania, Philadelphia, PA.
Received November 10, 2008; accepted after revision May 1, 2009.
Reprints: Jay D. Amsterdam, MD, Depression Research Unit, University Science Center, 3rd Floor, 3535 Market St, Philadelphia, PA 19104-3309 (e-mail: firstname.lastname@example.org).
This research was funded by the National Institutes of Health/National Center for Complementary and Alternative Medicine grant AT001916. The authors' work was independent of the NIH/NCCAM, and the NIH/NCCAM had no involvement in the study design of this trial.
Trial Registration: Chamomile Therapy for Generalized Anxiety, NCT00645983, http://www.clinicaltrials.gov/ct2/show/NCT00645983?term=Chamomile+Therapy+for+Generalized+Anxiety&rank=1.