A recently published study indicates that a blend of citrus oils can, indeed, have anti-depressant effects. The goal of the study was an attempt to restore the mental health of humans by stimulation of the olfactory system. A citrus blend was created using a blend of Lemon, Orange and Bergamot Essential Oils with cis-4-Hexenol (a synthetic fragrance and flavoring chemical with a powerful green top note.) [Why the researchers had to use a synthetic in that mix I have no idea, it makes the results a lot more questionable, although if all they wanted to do was 'stimulate the olfactory nerve' I guess it doesn't matter!]
A group subjects, all inpatients receiving medications for depression, were selected and the group divided in half. The first group received their anti-depressant meds alone, the second were exposed to the fragrance continuously while having their meds reduced weekly until their depression remitted (within four to eleven weeks.) At the end of eleven weeks, all of the first group's depression had improved, but they all needed to continue on their full dose of medication. Among the fragrance group, nine out of the twelve had reduced their medication usage to zero, while the remaining three were able to reduce their dosage by 50-75%. Citrus fragrance caused the "cell surface markers" (one of the tests used to measure depression) to return to the normal range much more quickly than treatment with anti-depressants alone. Other physiological markers indicating depression, while starting out significantly high in both groups prior to treatment, were much lower in the fragrance group after the study period, compared to the group treated with medication only. It also appeared that the use of the citrus oils helped with immune system disfunction.
I've always called the citrus oils "the smilebringers"... it would appear that I was right. I have a friend who suffers from severe depression, which he treats with St. Johns Wort capsules, no Rx medication. This afternoon I fixed him an inhaler containing a mix of Orange, Lemon and Bergamot. (And I think I'll give him a small bottle of the blend for his car, as well.) Can't wait to see if it helps!
(citation from the Essential Oil Research Database.)