In a randomized clinical trial with an initial sample of 180 professionals, Kurebayashi and her colleagues studied the effectiveness of auricular methods (e.g. an auricular protocol for pain & anxiety) as a efficient, drug-free approach for improving the quality of life of the nursing staff of a hospital.
Results showed a 17% reduction in anxiety, a 36% reduction in pain, and a 13% increase in the mental aspect of quality of life. Details on descriptive statistics, analysis of variance (ANOVA) and Cohen's Index are included in the analysis. See link to NCBI.