Phenomenon that occurs when people are given a sugar pill and told that it is a drug that will help their disease. An astounding 16-33% in ANY study will say that it works. They represent people who would have gotten better anyway, who are suggestable, or well, whatever. The flip side is that they also report side effects. In any study of a drug's effectiveness, the rate of success and side effects are statistically compared to see how much good/harm the drug is doing compared to placebo.

A "dummy" version of a drug (e.g. placebo pill). It's a common practice in medical experiments to separate a test group into two parts, giving some of the patients the real pill, while to the rest, a "placebo", a neutral pill containing no active ingredient, both designed to look the same. The patients aren't told which one of the pills they've got.

Such tests allow the researchers to separate the actual medical effects aside from possible mentally-caused effects (e.g. "side effects" or suddenly getting better from the placebo). Apparently, power of persuasion can do wonders to our health.

According to an article in New England Journal of Medicine in May, 2001, there's no scientific basis for the placebo effect.

Research performed at the University of Copenhagen and the Nordic Cochrane Center, Rigshopitalet, Denmark studied statistics from over 700 trials that included tests of pharmacological, physical and psychological placebos.

When going through the results that involved some 7,500 patients, the researchers excluded all tests that did not compare placebo and no treatment at all. They then reviewed how the test subjects receiving no treatment compared to those receiving placebos.

The result was that there were little or no difference. "We found little evidence in general that placebos had powerful clinical effects" the researchers wrote. Only in the treatment of pain could a significant placebo effect be statistically verified.

This supports the theory that the placebo effect is based upon earlier experiences and expectations. The body simply produces more endorphins since this may have been the result of a previous pain medication, such as morphine. This kind of effects may however be negative, nocebo effect.

Source: Scientific American,

A lot of people mistake the placebo effect for alternative medicine, which is something different. It is common medical pratice to prescribe a placebo to a patient who thinks he or she *needs* medication.

It's also of paramount importance in pharmaceutical research, when new drugs are being tested it is important to filter out any other influence than the drug itself. This is done by blind or double-blind testing, in the former the patient doesn't know it's been given a placebo, in the latter the doctor giving the drug doesn't know he or she is giving a placebo(to filter out the influencing of a second person). Studies have found placebo effects with lots of medication, and these are renown researches.

Studies show a large negative correlation between the amount of stress (for a prolonged period) and the number of white blood cells in the blood. A proof that stress has a negative impact on the body's defence system. There's also lots of research on changes on a neurochemical level due to psychological changes, providing evidence of physical changes due to mental changes. It is all a matter of neuro-chemistry and mind. Wether one influences the other or vice versa is a different discussion.

The May 24, 2001 issue of the New England Journal of Medicine carried two pieces questioning the effectiveness of the placebo in certain circumstances. The main article was a study titled "Is the Placebo Powerless?— An Analysis of Clinical Trials Comparing Placebo with No Treatment" and was conducted by Dtch researchers A. Hrobjartsson and P. C. Gotzsche. There is also an editorial, The Powerful Placebo and the Wizard of Oz, by J. C. Bailar III.

I don't have access to the text of the study, but the Journal of the American Medical Association reports that the study was a survey of clinical drug trials in which there were both placebo and no treatement control groups, and compared the effectiveness of those two courses of action. What they found, apparently, was that for most of the 114 studies cited, there was little or no benefit to taking placebos over avoiding treament altogether. The summary continues,

"Placebos did appear to produce small benefits in studies in which the outcome being measured was subjective and continuous, and in trials of pain treatment."

Now, while this clearly warrants further investigation, it is not quite a damning condemnation of the classical notion of the placebo effect. The vast majority of clinical drug trials don't include both placebo and zero treatment control groups; and a good many studies these days don't include a placebo group at all -- often new drugs are compared to a control group that uses an existing treatment regime, for obvious ethical reasons. I believe I read a news item when the study was published that the researchers had to wade through over 8,000 studies to find the 114 they analyzed for their work. We cannot, therefore, assume that the coverage of study was broad or comprehensive. This is the normal process of science; while popular media likes to make strong statements about the results of this study or that, careful science takes small, measured steps, preferring a strong degree of confidence in a small step over a weak degree of confidence in a bold sweeping conclusion.

Certainly the placebo effect has been the subject of study before, and in the end a thorough discrediting of the placebo effect will have to come up with a well-documented and careful explanation for those results, either through methodological analysis of past studies or by finding a balance between the ideas that the placebo effect is huge and that the placebo effect doesn't work.

The Placebo Effect on Pain
Following is a description of how one goes about demonstrating this effect as well as an investigation of the chemical mechanism

The lovely young subjects are told that they will be participating in a trial to test the effects of a pain killer on their pain threshold. They then allow the professional researcher to slip a fairly thick needle into the vien in the crook of the elbow.

"I'm going to stomp on your foot now, Cassandra, and I want you to rate the pain on a scale from one to five," whispers the good scientist.
The scientist stomps and she screams "four."
"Igor, flip the switch to that pump over there. You are now receiveing the pain killer, Cassandra. In a moment I will again stomp on your foot, and perhaps with the fury of MethRat." (saline, merely, is pumped into Cassandra)
The scientist exerts a fair amount of force, and suddenly too, on the poor girl's foot, to which she replies "Two."
"You will now receive another dose of pain killer, young lady," hisses the scientist with an arbitrary amount of triumph. (Igor switches on the pump again, however this time Cassandra receives a dose of Naloxone.

Naloxone is an opiod antagonist. Opiods include heroin, hydrocodone(codeine), and methadone, as well as the endogenous endorphins.

"Again, Cassandra, I shall drive my heal into your soft pink toes," murmurs the scientist. This being done, she screams forth a number, and that number is Five.

Could she have been merely responding to what was expected of her? Perhaps her previous experience with pain killers had conditioned in her a response to release endorphins.

But perhaps, sweet Cassandra's belief effected the release of endorphins, which then inhibited her pain sense. And so when she was given Naloxone, those endorphins were blocked. Could it be, then, that belief is realized chemically?

"It's a nice demonstration of the placebo effect," the psychiatrist says to the woman on his couch, scooting his chair over to the large glass door that leads to the garden. A cat stands on the other side of the door, rubbing itself against the glass. The psychiatrist touches his fingers to the glass, stroking where the cat has pressed its ginger body, and the cat purrs deeply, as if it were really being touched. "I'm allergic to cats, actually, so this is a nice arrangement for me," he adds.

The woman smiles. "It's cute," she shrugs. "But fifty dollars an hour for cat analogies? I'd rather we talked about my marriage."

"Let's talk about the imaginary friends instead. It's where I was going with the cat, you know. You're aware that they aren't real, yet interacting with these false personas gives you more satisfaction than your actual relationships. Why is that, do you think?"

"Oh, I don't want to talk about that. I only mentioned it anecdotally."

"Then why see a psychiatrist? It's symptomatic of something, you know, these delusions. Social anxiety syndrome, maybe. Mild aspergers. Let's work with this, Sheila. Tell me when it began."

"Look, I just wanted somebody to talk about my marriage with. I don't have any real friends outside of my husband."

"Well, why not just talk to your imaginary friends about it? Why come to me? You're beginning to realize yourself that you've got to connect to the world outside your own person. It's indicative of understanding that you can't fulfill your own needs for companionship. It's a positive thing, Sheila."

The woman smiles again, and stretches her arms pensively.

"Honey, the Ryersons are here," calls a voice from outside the room. "I've been raving to them about that pot roast of yours!" The woman stands up and, shutting the door of the empty room behind her, goes to join her husband.

A few weeks ago I was having lunch with an old teacher of mine. He is a jolly Canadian man in his 60s, whose favourite topic of conversation is his many, many medical problems. He won't hesitate to tell anyone about his Hashimoto's thyroiditis, lumbar spinal stenosis, migraine headaches, peripheral neuropathy, or his various other aches and pains.

After filling me in on all the details of his most recent MRI scans, he said to me, "Now don't tell your mother, but I've also been getting some help from a homeopath lately." (My mother is his GP.)
"Oh really? What kind of help?"
"Well, I figured it couldn't hurt to try something alternative for this neuropathic pain of mine, I've tried so many other drugs."
"What did they give you?"
"Well, he's put me on these homeopathic drops. Just a couple on the tongue each night, and I tell you I've really noticed a difference."

I decided not to get involved in this one, and just made a non-committal "uh-huh" before asking about something else. I started wondering, though, whether it would have been right to argue the point with him. If he believes that his homeopathic drops, and not his gabapentin, are helping his pain, then should I argue?

You can probably tell that I am about to argue that I was right not to argue, but I have to confess that this is a special case. It's quite clear by now that his pain is not because of an underlying disease, it's just a symptom that he has to live with. If it were a serious, life-threatening condition that he was sprinkling water on, then this would be a different story. Or if he were seeing a homeopath instead of a doctor, rather than as well as several doctors. So my argument is restricted to only a subset of people who use those treatments that are probably just placebos. But I know there are a good number of people who do this—they go to their doctor, and then get themselves "centred" by someone who practices alternative medicine, without telling either of their healers that they are cheating on them.

With that disclaimer in mind, I think there are four possible ways a person might react if you tell them their placebo is a placebo:

  1. They don't believe you.
    Nothing changes, but you tried. Maybe you haven't done any good, but you've done no harm.
  2. They stop taking the placebo.
    Their symptom will probably worsen slightly (at least when it's pain we're talking about1), making them worse off. They will save some money, but they were willing to pay for the placebo before they knew the truth about it, so they must have felt that the improvement in their symptom was worth the money. In total, you have worsened this person's life.
  3. They switch to a "real" drug.
    This drug was already available to the person before you spoke to them, so they would have decided that, on balance, they preferred the placebo2. Perhaps, though, they didn't know about the real drug, or they didn't know how good it was, or they were just prejudiced, and they will be better off now if they decide to start taking it. You might have improved this person's life.
  4. They keep taking the drug, knowing that it's a placebo.
    Knowing it's a placebo ruins the effect, so their symptom will get worse, but they're still paying for it. You have worsened this person's life.3

So we have four possible outcomes, only one of which holds the possibility of improving someone's life, and even then it's a maybe.

And the placebo might not be a tablet or a drop of water. Think of "relaxant" candles, Feng Shui, aromatherapy, and dream catchers. A woman who buys fake pearls, thinking they're real. Is it wrong to tell her she is wrong, when she enjoys wearing them? Even religion, in the eyes of many atheists, is a placebo, but is it better to try to prove someone wrong or to let them believe something that makes them happier?4 Perhaps that's a bad example, since it's not a situation where people generally choose between several alternatives, but I think you can see my point.

Still, a lot of people feel that it's wrong to let people use a drug that "isn't real". Perhaps it is something to do with the profit margins of the company that is making these pills out of sugar. The next question then is, Why is it so bad for this company to make a profit, regardless of what they're selling? They have shareholders and workers who make a living from it. Is it wrong to use aspirin because it's also cheap to make? I think that, in the end, whether or not you think it's wrong to reveal the "true" nature of the placebo depends on how much moral weight you give to the truth in itself, removed from any questions of utility.

  1. Pain seems to be the only symptom that placebos can help to ameliorate significantly, or at least that's what the research has found so far.
  2. Of course, markets aren't perfect and not everybody would have "chosen" to take the placebo rather than the real drug. But in economics, although it's very complicated to talk about the behaviour of a single person, it's quite a lot simpler to talk about people in bulk, where aggregation leads to populations adhering fairly well to the predictions of theories that assume that everyone is well-informed about the products they consume. So, in general, although some people will be worse off with their new knowledge, the population as a whole already knew what it was doing.
  3. This may not be true. Tem42 has alerted me to the fact that placebos appear to have an effect, even if the patients are aware that they are placebos, so this would be equivalent/similar to situation #1: One more reason to let someone keep using them, it would seem.
  4. Eskimo: "If I did not know about God and sin, would I go to hell?"
    Priest: "No, not if you did not know."
    Eskimo: "Then why did you tell me?"

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