Comparison of the effect of lavender and bitter orange on anxiety in postmenopausal women: A triple-blind, randomized, controlled clinical trial.

INTRODUCTION: This trial compared the effects of lavender and bitter orange on anxiety in postmenopausal women.

METHODS: This trial was conducted in 2015. Eligible postmenopausal women were allocated into one of two intervention groups or a control group (n = 52 per group) in a 1:1:1 ratio using a randomized block design. Intervention groups received 500 mg capsules containing only bitter orange or lavender flower powder, and the control group received 500 mg capsules containing starch. The Spielberger's State -Trait Anxiety Inventory (STAI) was used before and eight weeks after starting the intervention. Data analyses were based on intention to treat.

RESULTS: A one-way ANOVA showed no significant difference in mean state anxiety (P = 0.254) and trait anxiety (p = 0.972) score among the three groups before the intervention. The general linear model, adjusted for baseline state and trait anxiety scores and confounding factors, showed significant differences among the groups in the mean state anxiety (P = 0.010) and trait anxiety (p = 0.041) score after eight weeks of treatment. Bitter orange significantly reduced the mean state-anxiety scores compared with the control group [Adjusted Mean Difference (aMD): -1.99 (95% Confidence Interval, -3.64 to -0.34)]. Lavender significantly reduced the mean state-anxiety scores compared with the control group as well [aMD: -2.45 (95% CI -4.13 to -0.77)] and Bitter orange significantly reduced the mean trait-anxiety scores compared with the control group [aMD: -1.76 (95% CI -3.45 to -0.06)]. Lavender significantly reduced the mean trait-anxiety scores compared with the control group as well [aMD: -2.05 (95% CI -3.76 to -0.33)]. There was no significant difference between bitter orange and lavender groups after intervention in the mean trait-anxiety (p = 0.731) or state-anxiety (p = 0.578) scores.

CONCLUSION: The positive effect of bitter orange and lavender on anxiety in postmenopausal women suggests that they can be used to decrease anxiety in such women.