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The Power of Suggestion Can Play a Role in Aromatherapy

Shira Cohen is studying Nutrition at the School of Dietetics and Human Nutrition at McGill University, specializing in Global Nutrition. 

Aromatherapy is based on the contention that specific fragrances can have different psychological and physiological effects. Lavender oil is said to be relaxing, while neroli, a scent extracted from the blossoms of the bitter orange tree, has a reputation as a stimulant. There is, however, a question of the role that suggestion may play in any effect that is experienced. To answer this question, researchers exposed ninety women to either lavender or neroli scent without identifying them. For each scent, some of the subjects were told that it was relaxing, others that it was stimulating. Heart rate as well as anxiety (measured by skin conductivity tests) increased in those who were told the scent they were smelling was stimulating and decreased in those told it was relaxing irrespective of what they were actually smelling. Questionnaires assessing mood revealed similar trends based on expectation. However, when no suggestion accompanied the odour, no stimulation or relaxation was noted. These findings suggest that benefits attributed to aromatherapy may be due to the placebo effect.

Not all studies, though, come to the same conclusion. In another trial, fifty-six volunteers were fitted with cotton balls under their nose that were infused with lavender, lemon oil or distilled water. Lemon oil, like lavender has a reputation for improving mood and relieving anxiety. Half the subjects were told about the supposed effects, the others were just told that they would be sniffing various scents. In this case, lemon oil enhanced mood and lavender did not, with expectation having no effect on the outcome. Monitoring of immune and endocrine function through blood and saliva tests showed no positive effect for either scent, calling into question claims that aromatherapy can enhance physical well-being. Still, the possibility of beneficial effects under certain conditions cannot be ruled out. In yet another study, patients exposed to lavender oil through an oxygen face mask before surgery required significantly less postoperative pain medication than patients who had not been exposed to the scent. Interestingly, lavender-scented pillows are now commercially available with claims of improved sleep. Who knows, they may actually work. Especially if you think they do.

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