Dirt Is Cheaper Than Prozac: Mood-Boosting Bacteria?

I've heard about exposure to dirt strengthening the immune system -- but could it make you feel better, too?

Treatment of mice with a ‘friendly’ bacteria, normally found in the soil, altered their behavior in a way similar to that produced by antidepressant drugs, reports research published in the latest issue of
Neuroscience. [...]

Interest in the project arose after human cancer patients being treated with the bacteria Mycobacterium vaccae unexpectedly reported increases in their quality of life. Lowry and his colleagues reasoned that this effect could be caused by activation of neurons in the brain that contained serotonin.

When the team looked closely at the brains of mice, they found that treatment with M. vaccae activated a group of neurons that produce the brain chemical serotonin. The lack of serotonin in the brain is thought to cause depression in people, thus
M. vaccae’s effects on the behavior of mice may be due to increasing the release of serotonin in parts of the brain that regulate mood.

The usual caveats are doubled here: it's a mouse study of a notoriously difficult-to-measure characteristic. But the principle is interesting ... what if the rise in childhood behavioral disorders was related to the shift from playing outdoors to playing inside?

Spring is here. Let's get dirty!

Getting dirty may lift your mood [press release]

(Note: Some of you conscientious Wired Blog readers may have already read this over at Bodyhack. That's because we're in the process of gathering our science coverage under the Wired Science tent. I'm one of the writers who will be joining Adam and Thomas, providing some nugget-sized blog morsels to complement their hearty fare. So if you've read Bodyhack before, thanks for coming along; and if not, I'm glad to be here and pleased to meet you. Hopefully we'll be reading a whole lot of each other!)