Emerging Insights on the Science of Mind over Body

Jo Marchant is a science journalist and author of Cure: A Journey into the Science of Mind-Body Medicine. She trained as a scientist and has a PhD in genetics and medical microbiology from St. Bartholomew's Hospital Medical College in London, England, and an MSc in Science Communication from the Imperial College in London, England. In this article, Dr. Marchant discusses how the mind can affect health, its limits, and current research in this field of medicine.

Q: What in your journey has led you to become involved in the field of mind–body approaches to health?

Dr. Marchant: Studying for my PhD taught me the importance of the scientific method for understanding how the body works, and I'm still committed to an evidence-based approach. When I later moved into science journalism, however, I encountered not just those people who are cured by modern medicine but those who are not. Examples are patients whose lives are devastated by gastrointestinal problems or fatigue yet are dismissed as not having “real” conditions, or people suffering from chronic pain or depression and are prescribed ever-higher doses of drugs that create addiction and side-effects but don't solve the underlying problems. I have also met people with autoimmune disease who are convinced that stress is contributing to their symptoms, and I have met parents who are reliant on alternative remedies—from homeopathy to amber teething bracelets—for relieving pain and discomfort in their children. I am skeptical of many alternative therapies, particularly those for which there is little or no research evidence to support their use. Yet, I couldn't deny that intelligent, educated people believed that these approaches were helping them in a way that conventional medicine was not. I wondered if what both sides were missing was the role of the mind.

Q: In your book, Cure: A Journey Into the Science of Mind Over Body , * what research did you find to be the most surprising or intriguing?

Dr. Marchant: There were so many things that surprised me. A simple visualization technique can reduce a person's risk of complications during surgery. Placebos still work even if a patient knows that he or she is taking them. Chronic stress doesn't just make people ill; it ages us. However, one of the most unexpected findings for me was that we can train our immune systems to respond to taste and smell. This works through Pavlovian conditioning, in which we learn to associate a psychologic cue with a physiologic response. This process was famously discovered by the Russian physiologist Ivan Pavlov when he trained dogs to associate being fed with neutral cues, such as a sound or a light. After the dogs learned the association, they salivated in response to the sound or light alone. Pavlovian responses occur in people too, and these responses influence a range of bodily functions, including the immune system.

A research team in Germany is triggering conditioned immune responses, using a distinctive green-colored, lavender-flavored drink. If a person consumes it several times together with an immunosuppressant drug, the drink will subsequently suppress that person's immune system even without the drug. The researchers have shown this in trials with healthy volunteers and people with dust-mite allergy, and are now testing to see if the same procedure can be used to reduce drug doses in patients who have kidney transplants—limiting side-effects and prolonging survival of the transplanted organs. The hope is that learned immune responses could also reduce drug doses typically prescribed to people with allergies and autoimmune diseases. Similar approaches are being investigated in other types of conditions too, including pain, Parkinson's disease, attention-deficit hyperactivity disorder, arthritis and cancer.

Q: What are the top two or three physiologic mechanisms through which the mind is able to affect health?

Dr. Marchant: The influence of the mind on the body is often seen as mysterious or magical, but it's really just biology, and we can understand it scientifically. There are two main mechanisms by which the mind influences the body. First, different mental states can trigger or suppress the production of neurotransmitters in the brain, such as endorphins, dopamine, endocannabinoids, and prostaglandins. These help to regulate human physiology and can create or ease symptoms such as pain. For example, when someone takes a placebo painkiller, that person's expectation that his or her pain will ease causes the production of endorphins, which ease pain by binding to the same receptors in the brain as opioid painkillers such as morphine. The second link between mind and body is the autonomic nervous system [ANS]. Through this branch of the nervous system, the brain regulates many aspects of physiology such as breathing, heart rate, digestion, and immune responses.

These processes usually happen without people being aware of them; one can't generally “will” changes, but they are influenced by a person's mental state. One example is the fight-or-flight response: When a person feels afraid or stressed, that person's heart rate and blood pressure rise, his or her pupils dilate, and blood is diverted from the person's gut to the limbs and brain. The Pavlovian responses described above are also mediated by the ANS.

Q: Neuroplasticity has received a lot of attention. What are your thoughts on this emerging field?

Dr. Marchant: I think it is very exciting, but, as with the role of the mind in health in general, we have to avoid getting carried away. Scientists are finding that the brain is remarkably adaptable, with new neurons being generated even late in life. That's great news, but, of course, there are limits to what the brain can achieve and recover from, and we're still working out what those are.

One area I look at in Cure is the effect of long-term stress on the brain. Chronic stress and depression leave a person with a smaller hippocampus and prefrontal cortex (the brain areas involved in learning, memory and emotion regulation) and a bigger, better-connected amygdala (which is involved in the emotional response to threat). This reshaping of the brain makes a person more vulnerable to future stress and to all of the physical and psychologic health risks that come with that. A person's experiences during the first few years of life seem to be particularly important for setting up how that person will respond to stress—and therefore the risk of chronic illness—for the rest of his or her life. However, neuroscientists are also finding that mind–body approaches later in life can help repair the damage. For example, an 8-week course of mindfulness meditation reversed the brain changes normally seen with chronic stress.

There are also many studies now suggesting that interventions, from meditation to volunteering, can protect people against—and perhaps reverse—changes in brain structure associated with aging. I think this shows the potential of reshaping care for the elderly not around managing their decline but harnessing their abilities and continued potential for growth.

Q: What are some of the limitations of the mind to heal the body?

Dr. Marchant: Through influencing aspects of physiology such as neurotransmitters, hormones and immune responses, the mind can have a profound influence on the symptoms people experience, the physiologic process of disease, and lifelong risk of getting sick. The mind can do this without the side-effects, toxicity, addiction, and costs associated with drugs.

However, the mind can only influence tools that the body naturally has available and can only work within the body's normal physiologic limits. So, the effects of the mind on physiology often aren't as large as those we can achieve with drugs, and, of course, the mind can't create or replace chemicals that the body isn't capable of making—insulin in a patient with diabetes, the chemotherapy drugs we use to poison tumors, or the antibiotics we use to treat infection.

It's also important to remember that people can't generally will changes to happen (patients can't simply wish pain away or tell a certain immune response to switch on). Instead of generic “positive thinking,” we need to develop evidence-based approaches—such as placebos, conditioning, virtual reality, visualization, and mindfulness—to trigger the specific responses that we want.

Patients will always need physical drugs and treatments, but the mind has an important role to play too. Rather than choosing one approach or the other, we need to learn how to use both together in an intelligent way.

Q: With the understanding of the power of the mind to heal, how do we avoid the dangers/stigma of people accusing friends and family members that they haven't healed because they haven't, for example, thought enough positive thoughts?

Dr. Marchant: This is an important point. I think much of the skepticism about mind–body medicine stems from a fear that it risks blaming the victim—that acknowledging a role for the mind implies that people get ill because they aren't being positive enough, or secretly “want” to be sick. There is also the danger of raising false hopes, wherein patients are conned into believing that their thoughts can magically save them when conventional medicine can't. When researching Cure, I interviewed a woman with breast cancer who had been told that her disease was caused because she didn't love herself enough. She rejected conventional treatment and, instead, stood in front of her bedroom mirror each day repeating: “I am beautiful.” When I met her, the cancer had spread to her bones.

Cases like this are heartbreaking. However, I don't think the answer is to ignore the overwhelming evidence for the mind's role in health. After all, we already manage similar risks in other areas. We know that diet and exercise are important in health, for example, and we don't deny this just in case people reject conventional medicine or blame themselves when they get ill. When it comes to the mind we have to be cautious, by sticking carefully to what the research tells us and not making exaggerated claims. And we need to get away from the idea that “positive thoughts” will somehow heal us. As I explain above, the effects of the mind on the body work through specific biologic pathways that have clear limits and are often not under conscious control.

Q: Is there any promising research in mind–body medicine that you are most interested in currently that you can share with our readers?

Dr. Marchant: I'm interested in acupuncture. Research on acupuncture is showing that some of the central assumptions in evidence-based medicine are not as secure as we might think. The first assumption is that if a treatment performs no better than placebo in a trial then that treatment doesn't work. In most (but not all) clinical trials, verum acupuncture performs no better than sham, or placebo, acupuncture. However, despite this, verum acupuncture can still work significantly better than conventional treatment. In one trial of >1000 patients with chronic low-back pain, there was no difference between verum and sham acupuncture, but both groups did nearly twice as well as a group of patients who received painkillers.

To Contact Dr. Jo Marchant

Jo Marchant, MSc, PhD

 London

 United Kingdom

 E-mail: jomarchant26@yahoo.co.uk

 Website: http://jomarchant.com

The second assumption is that if a therapy confers the same benefit as placebo in trials, then it is working through a placebo effect. In a recent series of trials, ^1,2 neuroscientists found that patients with fibromyalgia given either acupuncture or placebo acupuncture reported the same level of pain relief. However, positron emission tomography scans of the patients' brains looked quite different. In the placebo group, there was reduced availability of endorphin receptors. This is what one would expect, because placebos ease pain by triggering the release of endorphins. Meanwhile, the acupuncture group showed the opposite: These patients had increased availability of endorphin receptors. The researchers suggested that, rather than working through the placebo effect, the verum acupuncture triggered cells to produce more endorphin receptors. This is intriguing, because chronic pain syndromes such as fibromyalgia are characterized by a lack of endorphin receptors: Acupuncture may help redress the balance.

It is early for this research. However, I think it shows that by interpreting placebo-controlled trials in an overly simplistic way, we risk dismissing treatments and approaches that might have great potential for treating conditions such as chronic pain.   ■