General | March 6, 2015 | Author: The Super Pharmacist
There are many misconceptions regarding placebos and the placebo effect. This is true for patients, scientists, and physicians alike. The placebo effect is a subjective or objective result arising from a substance or procedure that is completely innocuous. Most people equate placebo with a sugar pill, i.e., a pill that contains nothing but simple table sugar in a gelatin capsule. Some people who take a placebo experience profound changes in health and well-being despite the fact that the pill or procedure should have no objective effect. This is called the placebo effect, and it has baffled scientists for generations.
Placebos have been used as tools in scientific research and in the clinic for over 100 years. Scientists currently use placebos as a comparator to an active treatment. For example, half of people in a clinical trial may receive a blood pressure medication while the other half receives a placebo. The effect on blood pressure in the treatment group is compared to the placebo group with the assumption that the placebo should have no effect, since it contains no active drug. Hundreds of thousands of clinical studies have been conducted this way, and the approach is widely accepted. The problem is that a substantial number of people derive a benefit from the placebo effect even though common sense would tell us that they should not. For these studies to be relevant, each group should not know if they are in the treatment group, taking the active medication, or the control group, taking the placebo.
There has been a plethora of putative explanations for the placebo effect. One of the more common explanations is that in people who perceive the benefit from placebo, the placebo works by expectation effect.
In essence, the placebo meets an expectation by the patient that the pill will work. In other words, because the patient strongly believes that the pill they are receiving will work, something in the brain makes that belief a reality.
Placebos may also work by the conditioning effect. Once people have experienced pain relief from taking a specific pill (one with real analgesics) who were then later given a placebo, the placebo relived pain.
In other words, the patients were conditioned to believe that a pill would relieve their pain. Since the placebo effect flies in the face of much of traditional Western medicine, there is a considerable amount of skepticism regarding the process and its neurobiological basis. Nevertheless, even most skeptics have conceded that the brain may be able to create a subjective reality for an individual patient, which underlies the placebo effect. If the patient believes that a medication works and that medication is real (not placebo), perhaps the brain can "trick" itself into perceiving a false reality.
This is not just a sort of magic or mental illness, the brain actually undergoes objective, measurable changes when a person is taking the placebo. For example, people who respond to placebo reported higher pain thresholds after taking the placebo than beforehand. Most impressively, placebo changed the way that the prefrontal cortex of their brain activated in response to pain after taking this placebo. In “nonbelievers,” the placebo had no effect on subjective pain intensity or pain processing in the brain. For reasons that are unclear, children and adolescents seem to be particularly amenable to treatment with placebo, especially for psychiatric illnesses. This has led to the hypothesis that there may be specific neurobiological pathways present in youth that may make better use of the placebo effect.
The placebo effect has been documented in several medical conditions. Some of the strongest evidence of the placebo effect has come from experiments in psychiatry and pain management.
A substantial number of patients treated with sham oral medications (a.k.a. placebo) or sham procedures experience a clinically meaningful improvement in nonspecific low back pain, perhaps as high as 70%.
The placebo effect has been documented in allergic rhinitis, overactive bladder, migraine headache and irritable bowel syndrome.
Even illnesses with seemingly objective biological effects to be treated with placebo, most notably asthma, Parkinson's disease, and even acne. While science has yet to explain how the placebo effect works, hundreds of studies have shown that it does.
How would you feel if you received a placebo without your knowledge? What if it worked? Using placebos in clinical practice brings up a number of ethical issues. Physicians have a duty to obtain informed consent from patients before starting any treatment. To supply informed consent, the patient must know the benefits and risks of particular medication. How can this be done with a placebo if the patient must believe that it works like a "real" drug it be told that it is a sugar pill? The American Medical Association has even taken the strong position that placebos may only be used if “the patient is informed of and agrees to its use.” This places physicians in a difficult position and largely limits the degree to which placebos can be used in clinical practice. On the other hand, there is a growing push to revise this position as we learn more about the neurobiological underpinnings of the placebo effect.
Astonishingly, recent research on the placebo effect suggests that the placebo effect seems to work even in people who know they are taking a placebo.
Researchers recruited women with irritable bowel syndrome (IBS) who had a score of at least 150 on the IBS Symptom Severity Scale and split them into two groups, one receiving a placebo and the other receiving no additional care. Unlike most placebo studies, the researchers in the IBS study did not hide the fact that individuals were receiving placebo. Women who knowingly took a placebo had significantly greater improvement in IBS symptoms than those receiving standard care.
These results suggest that “placebo without deception” may be effective in treating IBS symptoms and raise the possibility that placebo may work without "tricking" the patient. In fact, the placebo effect is so strong in IBS that researchers may need to find other ways to compare “active” ingredients rather than comparing it to placebo.
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