An investigation into the anxiety-relieving and mood-enhancing effects of Echinacea angustifolia (EP107™): A randomised, double-blind, placebo-controlled study

Abstract

Background: The acute anxiolytic effects of the echinacea angustifolia extract (EP107^TM) have been demonstrated in two previous human trials. The goals of this study were to examine the anxiolytic and mood-enhancing effects of echinacea angustifolia over a longer duration with a larger sample size.

Methods: In this 6-week, 3-arm, parallel-group, double-blind, randomised controlled trial, 108 adults with mild-to-moderately severe anxiety were recruited and randomised to receive either a placebo, 20 mg, or 40 mg of echinacea angustifolia, twice daily. Outcome measures included the Clinically Useful Anxiety Outcome Scale (CUXOS), Positive and Negative Affect Scale (PANAS), Short Form-36 (SF-36), and Bergen Insomnia Scale (BIS).

Results: Based on data collected from 104 participants, both doses of echinacea were associated with overall reductions in anxiety, although improvements were not different from the placebo. However, both doses of echinacea were associated with greater improvements in the PANAS positive and negative affect scores, and SF-36 emotional wellbeing score compared to the placebo.

Limitations: The positive improvements associated with echinacea were only identified via the secondary outcome measures and, therefore, require validation in future trials.

Conclusions: The echinacea angustifolia extract (EP107^TM) administered for 6 weeks at a dose of 40 and 80 mg daily was not associated with greater improvements in anxiety in adults with mild-to-moderately severe anxiety compared to the placebo. However, there were greater improvements in positive and negative affect, and emotional wellbeing, suggesting antidepressant effects. Further studies using clearly-defined populations and validated outcome measures will be useful in future trials.