The role of suggestion of hedonic quality in the olfactory remediation of pain
The use of aromatherapy as a form of complementary medicine is growing among European health care providers, and American interest is increasing as well. Despite the abundance of anecdotal reports and widely published claims of the efficacy of aromatherapy, there is very little scientific support for its use. The present study was aimed at investigating the claims made by aromatherapists in a controlled experimental setting. In this 2 x 3 design, there were two odor conditions (lavender and no odor) and three suggestion conditions (pleasant, unpleasant, and no suggestion) regarding the hedonic quality of the odor. Essential oil of lavender was diffused through the experimental room prior to the participants' arrival. The suggestion was given before exposure to the odor stimulus. Participants' mood and arousal were measured by the Semantic Differential Measures of Emotional State (SDMES), and hedonic judgement of the odor was assessed. The cold pressor task, which produces tonic pain, then yielded measures of pain threshold and pain tolerance. Participants were administered the McGill Pain Questionnaire, which provides measures of the sensory, affective, and cognitive/evaluative aspects of pain, as well as an overall pain rating index and measure of pain intensity. Participants completed the SDMES again, followed by a final assessment of the pleasantness of the room and a postexperimental questionnaire. Results indicate that the presence of the ambient odor did not effect pain threshold, pain tolerance, mood, or measures taken from the McGill Pain Questionnaire. Results support the hypothesis that participants in the pleasant suggestion condition would rate the ambient odor as more pleasant than those participants in the unpleasant and no suggestion conditions. These results do not support the use of aromatherapy as an intervention for tonic pain; however, many questions are yet unanswered and further research is needed in this growing area.