There’s a old schism in medicine: traditional treatments versus the healing power of the mind.

Now, though, science is weighing in, and doctors are hotly debating the role of the brain in addressing ailments.

“Why would we have evolved a mind if it didn’t have physical effects on our body?” asks Jo Marchant, author of Cure: A Journey into the Science of Mind Over Body.

Marchant, who has a PhD in microbiology, thinks that the connection between the two is obvious. “The whole point of having a mind is to improve our survival and fitness,” she says. And it follows that our brain is deeply entwined with our physical ailments.

Marchant points to symptoms of illness -- like pain, nausea, fatigue, or depression -- as warning signals. “Our awareness of those symptoms is telling us that something is wrong…. We need to move our finger from that burning stove; we need to stop eating that food that’s making us sick.”

And just as your physical state can affect your mind, mental states can create physical responses. Butterflies in your stomach? That’s actually the feeling of blood rushing from your stomach to other parts of your body, parts that might be very important in a fight or flight situation.

Still unconvinced?

We’re all familiar with the placebo effect. A sugar pill can be just as effective at blocking pain as a prescription pill. For a long time, that was chalked up to a psychological response. But studies have revealed that placebos can have the same biochemical effects as painkillers.

That means the brain is able to release its own set of endorphins independent of pills.

Care has all sorts of components, from your mental state to your physical condition. Marchant believes that it’s time to start “researching [the mind-body connection] in an evidence-based way.”

So the next time you get the shakes before a big event, just take a deep breath and thank your brain. It’s just thinking of the best way to help you perform.

Still curious? Here's an excerpt from Marchant's book about the link between autism, secretin, and the placebo effect.And here's a link to the study she references.