The Effects of Echinacea (EP107^TM) on Anxiety: A Comparison of Anxiety Measures in a Randomized, Double Blind, Placebo-Controlled Study

Background/Objectives. Beyond its well-known effects on upper respiratory tract infections, it was shown repeatedly that Echinacea extracts with unique alkamide profiles (EP107TM) decrease anxiety in both animals and humans. In a recent study, however, an extract identical to those used earlier failed to decrease anxiety more than placebo, although it enhanced wellbeing and induced anti-depressant-like effects as compared to placebo. The psychometric instrument used in this study, the Clinically Useful Anxiety Outcome Scale, focuses on physical symptoms of anxiety, whereas the State-Trait Anxiety Inventory that was employed earlier focuses on psychic symptoms. Methods. To study the influence of the anxiety measure on the detectability of anxiolytic effects, here we studied the effects of Echinacea EP107TM by means of the Hospital Anxiety and Depression Scale – anxiety subscale (HADS-A), which focuses on psychic symptoms, and the Hamilton Anxiety Rating Scale (HAM-A), most items of which investigate physical symptoms. The study was placebo-controlled, double blind and multicenter. Results. The extract significantly alleviated anxiety over the effects seen with placebo when studied with HADS-A. Total scores of HAM-A did not reveal significant treatment effects. However, Echinacea was superior to placebo in three psychic anxiety items of the HAM-A. Conclusions. Taken together, these findings suggest that Echinacea EP107TM efficiently decreases psychic anxiety without affecting somatic anxiety symptoms. This indicates that the preparation may be used in mild forms or incipient phases of anxiety when somatic symptoms are not yet accentuated.