About 15-20 percent of the population is hypersensitive, which makes those people more attuned to both sensory inputs — smell, touch, sounds — and emotions. Obviously, this can have its upsides and downsides, but like anything else, it's all about how you deal with the things that make you different. Oftentimes, those with ADD/ADHD are also hypersensitive (the two traits travel together on genes) and “[People with ADD/ADHD] often are hypersensitive in one of the sensory domains: sound, touch, or smell,” says Ned Hallowell, M.D., author of "Driven to Distraction."

You can check to see if you are more or less sensitive with a test like this one. (I checked 19 of the boxes; my partner would probably check all of them, so there are certainly degrees of sensitivity). Over time, I've realized that it makes more sense to understand and respect my sensitivities than try to ignore them — and one of the things I'm most sensitive to is scents. I've found that I can use that to an advantage when I want to influence my mood by using proven aromatherapy attitude adjusters. 

When I want to relax, my go-tos are either lavender or vanilla, both of which have been shown in studies to relax and mellow. But whether you are a more sensitive person or not, certain smells can have very real impacts on how you feel. How have scientists tested this? 

An article on the Social Issues Research Center's site reports: "Medical experiments have shown that vanilla fragrance reduces stress and anxiety. Cancer patients undergoing Magnetic Resonance Imaging — a diagnostic procedure known to be stressful — reported a massive 63 percent less anxiety when heliotropin (a vanilla fragrance) was administered during the procedure." 

Researchers at International Flavors and Fragrances developed Mood Mapping, which, according to the Chemical Senses journal, "reliably measures the mood associations of aromas, whether simple ingredients or finished fragrances in consumer products." They used Mood Mapping to compare reactions to a citrus aroma and vanilla, and found that in a test that used self-reporting, the citrus scent was overwhelmingly rated at being "happy" and "stimulating" whereas vanilla bean was rated as "happy" and "relaxing." 

While no scent is quite as happy-making as vanilla (it tops most studies for that quality — some theorize that it has to do with memories of childhood, while others say the effect is too strong and consistent for it to be a social effect), there's another that rivals it for relaxation.

Lavender has been found to be both relaxing and lightly energizing. In a 2012 Journal of the Medical Association of Thailand study,"... lavender oil caused significant decreases of blood pressure, heart rate, and skin temperature, which indicated a decrease of autonomic arousal. In terms of mood responses, the subjects in the lavender oil group categorized themselves as more active, fresher relaxed than subjects just inhaling base oil."

Of course, there's plenty more to be learned about aromatherapy (and plenty more science to do to parse out the real deal from the supposed effects of some scents). But even if you just have three essential oils in your arsenal — some kind of citrus (I like Aura Cacia's orange blossom), lavender and real vanilla (make sure it's not some fake stuff that uses chemicals to smell like vanilla, because lab tests show only the real stuff works) — you'll be on your way to happiness and relaxation, no matter how sensitive you are — though if you are highly sensitive, it might work especially well for you.

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Starre Vartan ( @ecochickie ) covers conscious consumption, health and science as she travels the world exploring new cultures and ideas.