Placebo Effect

Most of the people should be familiar with the Placebo Effect.

“Placebo Effect: the tendency of any medication or treatment, even an inert or ineffective one, to exhibit results simply because the recipient believes that it will work.”

Mom is a devout believer in traditional Chinese medicine philosophy (Yin and Yang and Five Phases Theory) and active practitioner of a repertory of Chinese medicine therapies, such as moxibustion and gua sha. As her daughter, I got the chance to experience many. Do they work? It seems to work for me. Do I believe in Chinese medicine? It is hard to say but certainly not to the extent that mom believes. I take it with a grain of salt. It has worked a significant amount of times in the past, and I do think it truly worked sometimes. However, I don’t know how often it was due to the placebo effect.

In the past 2500 years, a group of gowned ancient Chinese doctors devised esoteric theories healing the human body. Chinese medicine involves formulas of 10 to 20 herbs or minerals that a practitioner adjusts weekly after a consultation with a patient. And yet almost no research has been done on how these formulas interact with the body. Sorry, mom, I know you may get upset about me not respecting our culture. But it is not about culture. It is related to randomized experiment.

There has been a big, century-long debate on Chinese medicine. So I am not going to continue here, and I can’t get anywhere follow that direction either. What I want to talk about is an article from FiveThirtyEight “Surgery Is One Hell Of A Placebo” by Christie Aschwanden.

Chinese medicine certainly falls short of the scientific randomized experiment. To my surprise, the article points out studies have shown that many surgeries, including some common ones, failed to produce better results than placebo.

What is surgery placebo? It is a research technique called sham surgery. Patients are taken through all the regular pre- and post-surgical rituals, from fasting to anesthesia to incisions made in their skin to look like the actual operation occurred, but the doctor does not perform the surgery. If awake, the patient will even see a video of someone else’s procedure as if it were his own, and hear the sounds and sensations of a true surgery that the doctor mimics.

There are a lot of people suffer from chronic pain in the knee. There is a common orthopedic procedure in the United States that can diagnose and treat problems in the knee joint called “arthroscopic knee surgery”, with about 692,000 of them performed in 2010. The theory behind the surgery is:

The reason is straightforward, and the patient did feel better after surgery. So it should have no problem. That’s why surgeons believe that they are doing the right thing for a long time. However, an experiment by orthopedic surgeon Stuart Green, a professor at the University of California Irvine, showed that when done to address degenerative wear and tear particularly on the meniscus,
the procedure was no better than a sham. Meniscus repair is not the only one. The author mentioned some other operations that have been proven to be no more effective than a sham at reducing pain in the long-term, vertebroplasty (a back operation), intradiscal electrothermal therapy (a “minimally invasive” treatment for herniated disks and low back pain). What more weird is that invasive procedures produce a stronger placebo effect than non-invasive ones. Cutting into someone appears to provoke stronger placebo effect than injection. The latter is more powerful than taking a pill. How come the placebo effect? The articles mentioned three possible reasons:

(1) Patient’s expectation helps. When they got through all the regular pre- and post-surgical rituals, sensed the confidence of the surgeon, they believed that it would fix what ailed them.

(2) Another explanation is related to the statistical concept of regression to the mean.

“Regression to Mean: if you are doing bad, chances are your performance will regress to the mean and not because of any marked improvement. [The Art of Thinking Clearly by Rolf Dobelli]”

A patient may receive the treatment when the pain at its peak and the release after surgery could be the result of natural course, i.e. chronic pain peaks and wanes itself.

(3) The cause of the pain is often not as straight forward as people think. If a patient comes with pain in knee and an X-ray shows meniscus wear, it is no brainer to assume the worn meniscus causes the pain. So repair the meniscus. However, you can find all kinds of “abnormalities” even among people without knee pain. Why not everyone has the symptom? In fact, there is no necessary connection between pain and injury. Since we don’t know why this pain occurs, it is not surprising that we don’t know why it diminishes.

All in all, here are some takeaway points:

  1. The placebo effect is widespread.
  2. Many conventional treatments, even surgery, are not better than placebo.
  3. It’s hard to claim causal relationships in this complex world.

The use of randomized trials as a scientific method to determine the real effect of therapy is a significant step in distinguishing modern medicine from traditional medicine. But as we have seen, many mainstream treatments can not pass this test. But I do not want to complain about medical care. We have never been perfect but have been improving. What I am wondering are the following questions:

  1. In the digital and internet world, how can we identify the quality of information? How many “facts” we learn from whatever channels can pass the test?

  2. What will be the consequence if we don’t try to screen the information but take it through our color tinted glasses (i.e., we see what we want to see, hear what we want to hear)?

  3. In 1948, the sociologist Robert Merton coined the term self-fulfilling prophecy.

    “Self-fulfilling prophecy is, in the beginning, a false definition of the situation evoking a new behavior which makes the originally false conception come true. “

    It means that expectations are likely to influence our development which is not new. But how big is the impact? George Bernard Shaw’s play “Pygmalion” is a classic makeover tale—the story of a professor who transforms a working-class girl into an upper-class lady. Is Pygmalion effect a significant factor in producing and maintaining gender and racial gaps in IQ testing, GPAs, and college success?

  4. If belief is that impactful, what should we believe?

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