Mind Over Body: Studying the Placebo Effect

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Biology 202
2004 Second Web Paper
On Serendip

Mind Over Body: Studying the Placebo Effect

Mridula Shankar

"The power which a man's imagination has over his body to heal it or make it sick is a force which none of us are born without. The first man had it; the last one will possess it." -Mark Twain, 1903 (4).

You've been experiencing shooting pains down your shoulder blades along the sides of your back for a week, ever since you woke up the morning after that intense rugby game. You decide its time to see the physical therapist. Twenty minutes into the consultation and he has made note of your history, asked you to perform some maneuvers and given you instructions to ice and stretch those constricted muscles. "If the pain persists for a couple of days," he says, "take some ibuprofen." On the drive back home, you're already feeling better. Two days later you're back on the field feeling invincible. The answer to this miraculous recovery could lie in the mysterious, highly controversial benefits of the placebo effect.

The placebo effect is the "the measurable, observable, or felt improvement in health not attributable to treatment. This effect is caused by the administering of treatment that has no intrinsic therapeutic value in the healing process (1),(5). The Placebo effect first caused waves in the medical community when in the 1950's, Henry K. Bleecher of Harvard University published experimental findings which suggested that a significant number of patients (30-40%) suffering from chronic ailments improved after taking a placebo. (5) Over the decades the astounding advancements in medical technology and efficacious procedures have enhanced the quality and longevity of peoples' lives. Concurrent studies investigating the placebo effect have yielded unexpected results, often lessening the legitimacy of drug treatments with serious implications in the ethical, scientific and medical worlds. My research in this area stems from an interest in the neurobiological implications of such studies with a view towards understanding the psychological vs. physiological aspects of the human brain-body relationship. This paper will investigate the placebo effect, outline some plausible causes, study the ethical dilemma surrounding these inert substances and attempt to gain an understanding of the phenomenon through a study of the complex brain/body relationship.

In a study conducted by Tor D. Wager and colleagues, participants were exposed to a series of electric shocks.(7) At some point during the course of the experiment, a placebo skin cream was administered to a certain proportion of the participants. About 70% of these participants claimed to feel less pain after the application of the skin cream. Analysis of data collected using a functional magnetic resonance scanner gave evidence of reduced activity in parts of the brain associated with pain perception in participants who felt reduced pain. (7),(8) So what triggers these results? The answer might lie in the brain=behavior theory. While the placebo has no visible pharmacological effects, its psychological effects generate expectations in the mind of a patient of a certain consequence (a reduction in pain.) This expectation in turn influences the perception of feeling (In this case analgesia.) (7) The brain relies on the sensory input it receives. Thus the brain is continually changing in response to (supposed) altering stimuli. These neurological changes in turn cause behavioral modifications. Thus one might understand the placebo effect as essentially a biological change that results from a change that is largely psychological.

These findings also showed that the 70% who reported a reduction in pain showed a pattern of brain activity that was different from those that did not. (9) This result suggests a degree of plasticity of the human brain. Studies conducted by Walter A Brown confirm that depressed patients who respond to placebos differ in their biochemical pathways from those who do not respond to placebo treatments. (5) This could explain why only 70% of those treated with placebos in the shock experiment responded with the reduced feeling of pain whereas the other 30% did not.

Neurologists in British Columbia used PET scans to determine the amount of dopamine activity in the brains of patients with Parkinson's disease when given either a placebo or a drug that mimicked dopamine. Results showed that the brains of patients given the placebo responded by releasing as much dopamine as those that got the active drug. (3) If a placebo can induce the same result as an active drug then is there something more powerful than the chemical substance that causes this change? It turns out that the effectiveness of treatment is also a function of the mental approach of the patient receiving the treatment as well as the attitude of the physician administering it. (5)

Studies have proven that the biochemical responses to anti-depressant medication largely depend on the faith and mental outlook of the patient towards the treatment. (1) A patient who has high expectations of improvement is more likely to feel better than a skeptic. A thorough consultation with the doctor and the act of undertaking a therapeutic process boosts the confidence of the patient and gives one a sense of control over a condition that was previously hopeless. The alleviation of anxiety and generation of positive emotions trigger physical changes such as the activation of endogenous pain control centers that release endorphins to reduce symptoms of illness. (1) This explanation could give one a better understanding of the high success rate of homeopathic (and other alternative) treatments that use natural remedies to cure ailments. Charismatic practitioners make use of trust and beliefs of the patients to induce the body's own healing processes to bring about a change. (1)

If placebos are seen as broadly effective therapeutic devices, then why is their use so controversial? The mysterious power of the placebo effect is responsible for the ethical dilemma it causes. The placebo essentially makes use of the fact that if the brain can be "tricked" into thinking that the brain/body is being treated for an illness then it will trigger the necessary natural biochemical processes to bring about the change. If this is indeed how the placebo works then why are patients administered active drugs? The answer lies in the fact that the use of therapeutic placebos involves deception on the part of the practitioner. (1),(2),(4) It violates the fundamental principles of trust and faith that the doctor-patient relationship is based on. Yet it is ironic that it is this very violation that is responsible for the success of the placebo effect. Studies have shown that patients exhibiting the placebo effect stop doing so once they are told that they are on a placebo. Using the brain=behavior theory to interpret this result, it seems as though the brain in response to new conflicting information sets off a negative psychological feedback process which in turn induces the biological change that is seen as a resistance to the placebo.

Conflicting research results regarding the legitimacy of the placebo effect have also been a cause of concern. Recent research conducted at the University of Copenhagen produced results that disclaim its authenticity (1),(3). While some trials showed results, these successes were not significant enough to prove the powerful clinical effects claimed of these inert "drugs." Thus at present, the dearth of scientific knowledge regarding placebos, the lack of awareness of the manner in which they bring about change and other ethical issues surrounding their use has left the phenomenon of the placebo effect in a shroud of controversy. Yet this need for caution must not negate the genuine findings of clinical researches and dismiss entirely therapeutic placebo procedures used by practitioners.

We have become a pill popping society who has succumbed to the manipulations of large pharmaceutical companies. Intriguing phenomena such as the placebo effect reveal the healing power of the brain and environment. (4) A comprehensive understanding of this phenomenon requires an in-depth knowledge of the complex brain, and its neural mechanisms, a process that is still in its infancy. Yet results of studies are promising and who knows sometime in the future we just might be able to make those dummy pills work as well as drugs.


1)The Skeptic's Dictionary, the placebo effect.
2)Tamar Nordenberg, The Healing Power of Placebos. FDA Consumer magazine, January February 2000
3)W. Wayt Gibbs, All in the Mind. Fact or Artifact? The Placebo Effect May be a Little of Both . Scientific American, 2001
4)Kenneth E. Legins, Is Prescribing Placebos Ethical? Yes. American Council on Science and Health (1997 & 1998)
5)Walter A. Brown, The Placebo Effect. Scientific American (1997)
6)American Psychological Association press releases, Placebo Effect Accounts for Fifty Percent of improvement in Depressed Patients Taking Antidepressants.
7)Tor D. Wager, James K. Rilling, Edward E. Smith, Alex Sokolik, Kenneth L. Casey, Richard J. Davidson, Stephen M. Kosslyn, Robert M. Rose, Jonathan D. Cohen, Placebo-Induced Changes in fMRI in the Anticipation and Experience of Pain. Science Magazine (February 2004)
8)Dennis O'Brien, Brain response to placebo found: Study says pain reaction differs if patient believes treatment is effective Dennis O'Brien, Brain response to placebo found: Study says pain reaction differs if patient believes treatment is effective. The Baltimore sun Company (February 20, 2004)
9)Jerome Burne, Cured by an Imposter. The Times (London) (April 10, 2004

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