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The science of using your expectations to relieve pain

Traditional healing is used around the world, from acupuncture to laying of hands to yoga. How do these alternative remedies work to heal the body and the brain? As part of our series ScienceScope and in cooperation with the Pulitzer Center on Crisis Reporting, the NewsHour’s Nsikan Akpan ventures to Oaxaca, Mexico to dive into the neuroscience of expectation.

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  • Nsikan Akpan:

    Science writer Erik Vance has traveled the globe to learn how healing works, whether its Western medicine or traditional healing; 6,500 feet up in the mountains of Mexico's Sierra Mazatecas, we explored two things that sometimes unite those types of treatment – the theater of medicine and the science of placebos.

  • Erik Vance:

    My favorite one is — I don't know if you have ever, like, taken a pill and had — like immediately felt better. Like, as soon as you take a pill, your headache just goes away.

    Well, that pill actually takes 20 minutes to kick in. So what you're feeling is actually the placebo effect.

  • Nsikan Akpan:

    Placebos do this by unlocking the body's medicine cabinet, releasing compounds like appetite hormones or pain-relieving opioids.

    But in his book "Suggestible You," Vance explains how a placebo effect can be triggered by more than a sugar pill.

    Here in Huautla de Jimenez, many experience the placebo effect before they even arrive, through collective expectations made by the city's reputation.

    Curanderos, or traditional healers, have existed in this town of 36,000 since before the Spanish arrived. They're best known for introducing the West to psychedelic mushrooms in the 1950s. But they mainly rely on a blend of Christian symbols and indigenous healing practices to treat illness.

    Parents have passed on these cleansing rituals and cultural garments for centuries.

  • Fabiolo Garcia (through translator):

    The most important thing is that the next generation sees exactly which leaves I'm using in massages or drinks. I'm proud I'm teaching my daughter.

  • Nsikan Akpan:

    Curandero Placido Arturo, who has practiced for 40 years, uses herbs and spiritual blessings to treat everything, from toothaches to infertility.

    These settings form a theater of medicine.

  • Erik Vance:

    A lot of placebo involve storytelling, to pull someone out of their everyday, shock them a little bit and try to create a story that forces your brain to start treating itself.

  • Nsikan Akpan:

    The shock from these fire ants relieved Erik's forearm tendinitis. The ant bites are an active placebo, a sensation that convinces the body to open up its medicine cabinet.

    The next day, we visit curandero Elodia Pineda Garcia to see if this theater can treat my lower back pain. She blesses me, rubs my lower back. And at the end of the ceremony, she spits water in my face to cleanse my spirit.

    OK, at this point, I was skeptical. But I walked away feeling a surprising amount of relief, relief that lasted for months.

    To learn why, let's leave Huautla for a moment and visit the University of Maryland, Baltimore.

  • Dr. Luana Colloca:

    We call this social learning in placebo effects. So, for example, if a patient observes another patient getting a benefit from a therapeutic treatment, this can create strong expectations.

  • Nsikan Akpan:

    Neuroscientist Luana Colloca, whose lab is funded by the National Institutes of Health and others, studies how placebo effects can influence pain disorders.

    While physical injury causes pain, the brain can amplify or even create these pain signals merely through the expectations of feeling bad or through stress.

    Her lab uses fake ointments, hot heating pads and functional magnetic resonance imaging, or FMRI, to spot brain areas responsible for pain-fighting placebo responses. In a simplified version, we test my susceptibility to placebos.

    When the pad becomes painful, I click a mouse and the heat subsides. After gauging my pain tolerance, I rank how much pain I'm feeling from zero to 100. Then the screen turns different colors.

  • Dr. Luana Colloca:

    Any time the light is red, you will receive a high level of pain.

  • Nsikan Akpan:

    When its green, she says, the same pain gets delivered, but an electroshock probe inside this wristband attached just below the heating pad will soothe my pain nerves.

  • Dr. Luana Colloca:

    How much do you expect that this procedure is going to reduce your level of pain?

  • Nsikan Akpan:

    Maybe by half?

  • Dr. Luana Colloca:

    By half. OK.

  • Nsikan Akpan:

    Yes, that one is not bad at all.

    Of course, the probe is a prop. I receive the same hurtful heat every time. Yet, the pad felt cool when the light was green. Weirdly, my pain perception dropped by exactly 50 percent, suggesting an expectation for healing can be controlled.

  • Erik Vance:

    A doctor can also create a placebo effect and add that placebo effect to the power of the medicine. So it's in the way that they talk to you. It's in the clothing that they wear. It's in the environment that they choose to be in.

  • Nsikan Akpan:

    Luana's lab is using these placebo responses to build drugs and psychotherapies. They found a nasal spray of the hormone vasopressin can mimic the social placebo effect and provide pain relief.

    While placebos can't remedy something like cancer, to some degree, they have been shown to ease the symptoms of conditions like depression, addiction and autism.

    With Parkinson's disease, placebos can improve motor ability, and those effects can last for years. So, whether you're with a doctor in Baltimore or a curandero in the Mexican mountains, these healing placebos are never too far away.

    Until next time, I'm Nsikan Akpan, and this is the "PBS NewsHour" reporting from Huautla de Jimenez.

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