The efficacy of bergamot essential oil inhalation on alleviation of stress and anxiety and enhancement of positive affect : a randomized controlled trial

Abstract

Anxiety and stress are physiological or psychological responses that may cause serious mental and physical problems for individuals, and huge societal cost. Aromatherapy (the therapeutic use of essential oils) is a widely used alternative treatment that has been utilized to attenuate anxiety and stress due to its high safety and accessibility. Bergamot essential oil (BEO) is a popular choice of essential oil for its anxiolytic and mood-enhancing properties. This study is a double-blind randomized controlled trial that sought to empirically examine the effect of BEO inhalation on levels of state anxiety, stress and positive affect and the moderation effect of hedonicity on the efficacy of BEO, with a large sample recruited from general population (n=240), a placebo (artificial fragrance with an odor similar to BEO) and a control (unscented oil). Results of the current study showed that after a 15-minutes session of inhalation of BEO from a necklace, a greater reduction in state anxiety and stress was found in the experimental (BEO) group, compared to the placebo and control groups between which no difference was found. For positive affect, although it was found that it decreased after the session, the experimental group managed to maintain at pre-session level, while both of the placebo and control groups yielded significant decreased. Moreover, it was found that the effect of BEO was not affected by participants’ hedonicity of BEO (only for experimental group), and participants’ identification of the odor was also found to have no impact on the effect of BEO. This study has provided empirical evidence that BEO is more effective in attenuation of state anxiety, stress and improvement of positive affect than artificial fragrance that has a similar odor, and that the efficacy of BEO can be attributed more to its intrinsic pharmacological properties than to the psychological effects it induces.