Major Finding: At 8 weeks, the mean total HAM-A score for 28 patients given chamomile extract was 3.17 points lower than the score for 29 patients given placebo.
Data Source: A randomized, blinded, placebo-controlled clinical trial in 57 patients with mild to moderate generalized anxiety disorder, with and without depression.
Disclosures: The study was funded by the National Institute of Mental Health. The lead investigator and both presenters of the study have no relevant financial disclosures.
BALTIMORE — Chamomile extract therapy demonstrated both anxiolytic and antidepressive effects in a two-part randomized, controlled, blinded study of 57 patients with mild to moderate generalized anxiety disorder.
The initial study, published in 2009, is thought to be the first controlled clinical trial of oral chamomile (Matricaria recutita) extract for GAD. A substudy presented in a poster at the annual meeting of the Anxiety Disorders Association of America (ADAA) investigated the effect of chamomile on depressive symptoms in GAD patients who had comorbid depression, a history of depression, or no depression.
Since not all patients are willing or able to use psychopharmacologic treatment, “identification of a safe and effective herbal remedy for treating anxious and depressive symptoms would be of public health relevance,” Matthew A. Shore and his associates said in their poster.
Chamomile has long been used as a traditional remedy for its calming effect, and has demonstrated pharmacologic activity in animal models of anxiety, said Mr. Shore and his associates of the University of Pennsylvania, Philadelphia.
The original study, led by Dr. Jay D. Amsterdam, was summarized by coauthor Irene Soeller, a nurse practitioner, at the ADAA meeting. The 57 GAD patients all had minimum baseline Hamilton Anxiety Rating (HAM-A) scores of 9 or more. Patients with other DSM-IV axis 1 disorders, such as minor depression, were not excluded as long as the comorbid condition was not the primary diagnosis. Those with major depressive disorder, bipolar disorder, or other serious psychiatric diagnoses were excluded (J. Clin. Psychopharmacol. 2009;29:378–82).
Twenty-eight of the patients were randomized to chamomile extract and 29 to placebo for 8 weeks. Identically appearing and smelling capsules contained either pharmaceutical-grade chamomile extract or placebo. Initial dose was one capsule (220 mg for the chamomile) daily for the first week, increasing to two capsules daily for week two. After that, patients with a 50% or less reduction in HAM-A scores at each week were increased to three capsules at week 3 and four at week 4, and then up to five capsules at weeks 5–8 if response was still less than 50%.
At 8 weeks, there was a significantly greater reduction in the mean total HAM-A score for chamomile versus placebo—the primary outcome—with a mean difference of 3.17 points between the two groups.
The study was not powered to detect statistically significant group differences in secondary outcome measures. However, there were clinically meaningful changes in the same direction as the primary measure, including a somewhat greater reduction in mean total Beck Anxiety Inventory (BAI) scores with chamomile (difference of 2.09 points), a somewhat greater increase in mean Psychological General Well-Being (PGWB) scores (6.33) and a somewhat greater reduction in the Clinical Global Impression-Severity score (0.43).
There was also a somewhat greater proportion of overall HAM-A responders to chamomile vs. placebo (57% vs. 38%), and the overall percentage change was numerically greater for chamomile than placebo on both the HAM-A (53% vs. 35%), the BAI (42% vs. 21%) and the PGWB (28% vs. 18%).
Two patients discontinued treatment because of adverse events. One had an allergic reaction to the placebo, and one had abdominal discomfort while taking chamomile. There were a total of 33 reported adverse events, 11 on chamomile and 22 on placebo. The proportions of patients reporting one, two, or three adverse events did not differ significantly, and there was actually a lower incidence of adverse event rates at higher chamomile doses, they said.
The follow-up study divided the 57 GAD patients into three groups: 19 with comorbid depression, 16 with a past history of depression, and 22 with no current or previous depression.
In all three groups combined, there was a significantly greater reduction over time in total Hamilton Depression Rating (HAM-D) 17 scores and in core HAM-D depression items (including depressed mood, guilt, and suicidal ideation) for chamomile versus placebo, with a P value of less than .05 on both measures.
Nonsignificant yet clinically meaningful reductions were seen with chamomile vs. placebo in HAM-D 17 score in the group with current comorbid depression (P = .062) and in core HAM-D depression items in the patients without current or past depression (P = .06).