Last month, an article I'd authored was reprinted in Aromascents Journal. The article, Olfactory Memories, Olfactory Imagery and Their Influence on Behavior also appears in the Aromatic Library section of Aromaceuticals' website. I've gotten a couple queries indicating that some readers misinterpreted what was written, and I want to set the record straight: studies on olfaction which feature fragrance materials do not necessarily involve the use of essential oils.
My article gave an overview of several recent scientific studies involving the effects of odorants on behavior. In one Australian study (Prescott and Wilkie, 2007), subjects exposed to sweet aromas had higher pain tolerance than those exposed to unpleasant and/or non-sweet aromas. At least one reader interpreted this as "sweet essential oils are more effective for pain management than non-sweet essential oils." This is not what was written, and not necessarily true.
My source material did not indicate what specific aromatic substances were used to conduct the experiment. This is very typical of studies involving the use of odorants, which are often single or blended concoctions composed of artificial chemicals, or sometimes individual chemical isolates removed from natural substances. Why are synthetic or incomplete substances used? Many of these experiments are funded by large companies such as Monell or IFF, which manufacture aromatic chemicals for the fragrance and flavoring industries. Essential oils are rarely used as odorants in these studies, and when used often do not originate from named botanical sources. Therefore, it cannot be assumed that any conclusions drawn from these experiments can be applied specifically to aromatherapy.
In 1993, I attended an aromatherapy conference where Dr. Alan Hirsch presented a study on the effect of odorants on male sexual arousal. He tested a number of different aromas, and found that the most "arousing" were lavender and pizza. When conference attendees asked what specific lavender essential oil was used, Dr. Hirsch was unable to give a named botanical source. And obviously, essential oil of pizza does not exist.
One oft-cited study implicated peppermint in sleep disruption. Although the resulting research paper referred to "peppermint", the odorant used in the study was in fact pepperine, a fragrance chemical which acceptably mimics the scent of peppermint. That particular experiment was sponsored by the Fragrance Foundation, a significant player in the perfume industry.
We cannot assume that fragrance chemicals or chemical isolates derived from natural fragrances have the same effect on the human body as true, whole essential oils. While many of these olfactory studies can (and should) serve as food for thought, we can only view the results of experiments using natural essential oils as being applicable to aromatherapy.
Prescott, J. & Wilkie, J. Pain Tolerance Selectively Increased by a Sweet-smelling Odor. Psychological Science, 18(4), 308-311. Retrieved September 11, 2008 from EBSCOhost Academic Search Premier database.
Damian, Peter & Kate. Aromatherapy: Scent and Psyche, 85-88. 1995. Healing Arts Press: Rochester, Vermont.