Placebos Work Even When Patients Know They’re Taking Placebos

October 8, 2016 at 3:00 am Stephanie Wolek Leave a comment

A placebo is a sugar pill or similarly ineffective treatment used in medical studies. The placebo acts as a control for comparison when studying the effectiveness of a proposed treatment. Often, patients will notice some improvement in their condition even when taking a placebo. This phenomenon is called the “placebo effect” and recent research is increasing scientists’ understanding of these events.

Deception isn’t necessary

Originally, it was believed that placebos only worked because patients thought they were being treated. In one study, patients with irritable bowel syndrome were treated with placebos. One group was told they were given a placebo with no additional information. The other group was also given placebos but the pills were described as follows:

“Placebo pills made of an inert substance, like sugar pills, that have been shown in clinical studies to produce significant improvement in IBS symptoms through mind-body self-healing processes.”

Both groups showed some improvement but the group given more information had significantly higher global improvement scores. The authors concluded, “Placebos administered without deception may be an effective treatment for IBS.”

The reverse phenomenon is called the “nocebo effect”

If a patient doesn’t think a treatment will be effective, they may experience a worsening of symptoms. This has been called the “nocebo effect” in medical literature. The effect can also be caused by doctors and other clinical staff. If the doctor feels negatively about a treatment or mentions likely side effects, it may affect the patient’s perception. This can cause an ethical dilemma. Doctors are required to properly inform patients of possible side effects or risks. Emphasizing the negative aspects of a treatment may make it less effective, however. More communication training in medical school may help physicians keep patients informed while also framing treatments in a positive way.

How a placebo is administered may change the effects

Some placebos work better than others and the method of administration can increase or decrease effectiveness. In one study, large placebo pills were found to be more effective than small ones and two doses worked better than a single dose. Sham surgeries and injections tend to elicit a stronger placebo effect than a sugar pill. In one study, a sham surgery was just as effective as an actual arthroscopic partial meniscectomy (a surgery used to treat knee osteoarthritis).

Placebos can be considered a viable treatment

Placebos are so effective in certain cases that some researchers have begun to recommend them as treatments. In an analysis of 130 placebo studies, one research team concluded that while placebos don’t work for many diseases, they were effective for pain. Placebos successfully treated pain in 27 different studies of various sample sizes.

Interestingly, placebos can also help treat symptoms of Parkinson’s disease. There have been multiple studies but one in particular stands out. Patients showed significant improvement when they were treated using deep brain stimulation, a technique that involves stimulating the brain with electrical impulses. The treatment was only effective when patients were also given a placebo and told that it was an “antiparkinsonian drug”. Patients who didn’t receive a placebo showed little to no improvement. A similar experiment was later conducted with identical results.

The placebo effect is still poorly understood and the use of a placebo can raise ethical concerns. Placebos may help treat pain, for example, but informed consent prevents a doctor from prescribing sugar pills. At the very least, placebo research provides insights into how expectation and perception can affect the outcome of medical treatments.

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Sources: book, nih.gov, jneurosci.org, aerzteblatt.de, nejm.org, nejm.org, sciencedirect.com, sciencemag.org, psychiatryonline.org, bmj.com