Effects of Melissa officinalis essential oil on state and trait anxiety

Introduction: Essential oils are complex substances used extensively in aromatherapy and phytotherapy, some of them as anxiety and stress-relieving agents. In order to evaluate the effects of Melissa officinalis essential oil on state and trait anxiety, this study was conducted. Methods: The essential oil was extracted by steam distillation and the chemical composition was investigated by Gas chromatographymass spectrometry (GC–MS). In addition, a Quasi experimental study with measures at pretest-posttest was conducted, where 58 participants were divided into two groups, a waiting-list (WL) control group, and an experimental group (EG)treated with aromatherapy based on Melissa officinalis essential oil. The anxiety index was evaluated by State-Trait Anxiety Inventory (STAI). Measures were taken at two times: pretest and posttest. Results: The chemical analysis showed that β-cubebene (26.3%), β-caryophyllene (25.4%) and geranial (12.5%) were de main components. Both state and trait anxiety levels decreased in the experimental group during the posttest phase; however, only state anxiety demonstrated statistically significant differences (p<0.05). A moderate size effect was found for state anxiety (d = 0.799; g= 0.797) with 1-β=0.803; but none for trait anxiety. Conclusion: Melissa officinalis essential oil was moderately effective on state anxiety but has no effect on trait anxiety.