Placebo Effect: Is it a Placebo?
With vast amounts of research and testing going on all over the world it is important to incorporate some method of control comparison. A placebo, a pharmacologically inert substance distributed in order to observe a medical effect or non at all. A response to the placebo is known as the placebo effect. If a placebo is considered a blank, why are they used? In order to answer this question one must consider the amounts of various tests and experiments currently in progress. There are psychological, neural, social, physical and philosophical tests performed throughout the world. Not only do the types of tests make an impact on the experiment but the subjects themselves; they vary in environmental conditions, financial situation, personality, time and age. .With a placebo one can somehow attempt to group the variables because they are already being combined in the experimental group.
In order to create a point of relevance to the subjects being tested, a group of individuals are given a parallel yet false treatment/test. The placebo was first incorporated into testing procedures around 1920 in order to obtain a negative control. The placebo, however, did not always bring about a negative control. When researchers found changes in the placebo group they began to investigate what was occurring. This later led to the discovery of the placebo effect, a positive effect to a pharmacologically inert substance or suggestion. Research was performed to figure out why this change was occurring? How is this possible? Is this experimental error? Are there other factors that led to these results? Is the placebo necessary as a control? Can testing occur with a control group that is not deceived? Is this ethical?
Although several ethical questions have been raised, deceiving the patient and withholding proper treatment, the necessity for placebo groups are essential for proper testing. The placebo group, if no placebo response is observed, gives the researchers a point of reference to compare the experimental drug effects. . If researchers were to control their experiments with a group who was not given any treatment, the subjects would realize they weren’t receiving treatment. This response hurts the experiment. Without a group that is receiving false treatment it would be difficult to tell whether the experimental group is benefiting from their treatment or whether the benefit is manifested. The placebo effect is a phenomenon that will be further explored to gain insight on its cause.
Although several benefits are obtained with a placebo group, ethics should not be ignored. In order to protect patients ethical standards were created by the Canadian Research Ethics Boards (REBS)  to insure that patients are not mistreated. Three ethical principles for human experimentation were created: 1-patients are to be respected, 2-researchers must maximize benefit while minimizing risks, and 3- the benefits and harms of research must be distributed equitably.. In order to reduce extensive placebo testing, REB must approve a proposal for this testing and proof must be provided that no “clearly effective therapies” exist for this test. In addition, clear guidelines on the proper use of placeboes are provided by REB in their Code of ethical conduct. Although there are ethical issues, there is a need for placebo testing that can benefit the greater good.
Let’s think about what a placebo effect is and what other factors could elicit a false diagnosis of this effect. In a study of two drugs, a tranquilizer and a stimulant, subjects were given four tablets, both inert, two red and two blue. The subjects were to try the tablets and fill out a questionnaire as to identify the tablet. In the questionnaire, majority of subjects stated that the blue tablets were the tranquilizers and the red tablets were the stimulant . The tablets were designed to elicit a color relation to the effects, which it did. A placebo effect was thereby observed because the subjects responded to the colors of the tablets and not to the pills. We can see this because of the blue/tranquil and red/hot color association.
Another experiment was performed in England where [835 women, who regularly used pain medicine for headaches, were assigned to four groups. One group received aspirin labeled with a common brand name, another group received the same aspirin with no brand name, the third group received a placebo with a brand name label and the last group received a placebo with no brand label. Among 435 headaches reported by group three, 64% improved within one hour of taking the medication while 45% of the 410 headaches improved in the first hour in the fourth group. The study demonstrated that the branded aspirin worked better than the aspirin with no brand and the placebo with a brand name worked better than the other placebo]. . Placebos were present; however, there was no placebo effect because of the brand label effect observed.
Many factors can affect the placebo effect. For this reason, experiments must be performed with caution. In order to test two different groups (one with a drug and the other with a placebo) to look for differences, it is important to replicate the entire procedure perfectly. In order to study the placebo effect, one must study the psychology behind it because the placebo is inert and therefore it is not causing the observed effect. The researcher must express the same amount of emotion, emphasis, logic, body language and interest in both the experimental and placebo groups in order to obtain true experimental data and determine whether a placebo effect occurred. If there were problems with duplicating and repeating the experiment then how would the researcher know if their results and comparisons were accurate? They wouldn’t.
Several theories were discovered to learn the cause of the placebo effect. Many hypotheses exist including the following: the conditioning effect, cognitive theory, motivational/anxiety theory, and response appropriate sensation. The conditioning effect is similar to Pavlov’s dog experiment where a repeated stimulus that leads to a response can be associated with a similar effect if there a false but similar stimulus. . An example of this effect occurs with individuals who commonly take Advil to eliminate headaches. With time and frequent use the individual will develop an association with the shape, color, and taste of the pill and therefore will experience the same effect with a placebo of the same physical appearance.
The cognitive theory is one that relies on expectation. Studies have found that instructions determine the effects of the treatment. For example, an individual is participating in a study of cognitive theory using amphetamine. The same individual could be given three different pills of the same amphetamine with three different instructions (stating different effects) and the individual will experience different effects from the same medication. This is a sympathomimetic effect. .
Motivational explanations and anxiety theories are also causes of the placebo effect. Motivational explanations are similar to the anxiety theory because they both occur because the individual desires the expected effect. The placebo calms the patient and reduces their anxiety because they feel like they are taking care of their condition/problem. They feel an effect because they want to feel this effect. .
The last cause of the placebo effect is called the response-appropriate sensation. This theory is a compilation of the above proposed theories. “[This theory] proposed that expectation-conditioning may represent a factor which determines the appropriate and behavioral repertoire with its associated sensation.”. Although a bit confusing, this theory relies on the expectation of a response to occur because they desire it to occur and this response occurs from an association that already exists. The example in the Benedetti et al. paper discusses an injured soldier. His expectation of death induces a behavioral response for survival while the injury remains inhibited. The pain the soldier experiences seems to disappear when he is moved to a safe place where he will receive treatment. The soldier expects to die, which elicits his survival mechanism, and yet he is preconditioned to believe that at the safe place he will receive treatment and therefore feels no pain only relief because his expectations calm him.
There are several hypotheses as to why or how the Placebo effect works but it does exist and it is important to consider this phenomenon during experimental procedures. In order to create a reference point of the experiment (how would this experiment be without the medical factor?), repetition is necessary while duplicating the same procedures that were given to the experimental group, with the same emotions and emphasis on the experiment while excluding the medication. Also, there are definitely ethical issues that should be addressed when working with a placebo group, however, groups like REB exist to monitor and guide proper placebo use. We have discussed placebos, the placebo effect and the underlying cause of the effect in order to prove that this is a real phenomenon. The placebo effect is not caused by experimental error but without a placebo group the physical effects of consuming small tablets cannot be obtained. This step is one that increases the accuracy of the results. Without this group experiments don’t hold as much validity only a guess with the hope that a placebo effect does not occur.
- Benedetti F, Mayberg H, Wager T, Stohler C, and J. Zubieta. Neurobiological Mechanisms of the Placebo Effect. The Journal of Neuroscience. 25(45):10390-10402. (2005).
- Benedetti F. and M. Amanzio. The neurobiology of Placebo Analgesia from Endogenous opiods to cholecystokinin. Progress in Neurobiology. 52(2): 109-125. (1997).
- Moerman D. and W. Jonas. Deconstructing the Placebo Effect and Finding the Meaning Response. Annual Intern. Med. 136:471-476.(2002).
- “Placebo Effect: Harnessing Your Mind’s Power to Heal” Mayo Clinic. Science Daily. http://www.sciencedaily.com/releases/2003/12/031231084101.htm (2003).
- Placebo Pro & Con. NCEHR Communique CNERH. http://www.ncehr-cnerh.org/english/communique2/Placebo.html. 8(2). (1998).