Placebo Effect, Part 1

In double blind clinical trials, patients are split up into two groups. In the case of an antidepressant trial, some of the patients are given the antidepressant and some are given a sugar pill (called a placebo) but no one, including the doctors, knows who got which treatment. As mentioned in previous posts, this is how the effectiveness of antidepressants is usually measured: the effects on the patients taking the real antidepressants are compared to the effects experienced by those taking the sugar pill. The placebo effect (the amount to which the sugar pill is described as effective) in antidepressant trials has been known to range between 15 percent and 70 percent response rates. It also seems that over the time, as antidepressant trials have been performed, the placebo effects documented in the more recent trials are higher.





The placebo effect is a powerful though not well understood phenomena of medicine and of life. To what extent can the power of positive thinking and expectation produce medical results? The basis of the placebo effect seems to be that if a patient expects to be affected by a medicine or treatment in a specific way, they are more likely to perceive that effects. In a way, this is similar to the concept of confirmation bias in psychology: if a person has an opinion, they will be more likely to notice evidence that supports that opinion. However, the placebo effect in a condition like depression that is significantly subjective in some aspects cannot be underestimated. The extent to which psychology can affect illness, especially mental illness, is still mysterious due to the limited knowledge of the causes of depression and other mental illnesses. Why have the placebo effect statistics in antidepressant trials increased over time? It is possible that as the drugs became less new and more commonly prescribed, public opinion of their usefulness increased thus increasing the placebo effect.

In this way, the placebo effect seems like a very good thing. If belief in a medicine alone is enough to produce improvement in depression symptoms, why bother with risky complex medications at all? The reason why sugar pills are not just prescribed in everyday life rather than antidepressants is as follows. The placebo effect is reliant on the patient's belief that they are taking an effective medicine, so obviously if a doctor were to prescribe sugar pills to a patient to attempt to induce a helpful placebo effect, the ethical and practical issues may be tricky. It seems inherent that a doctor should not simply lie to a patient. As the person taking the pill, the patient needs to know what the pill he is taking contains for medical safety reasons and because it is his right. In a clinical trial, the situation is more controlled and the participants know that they might be receiving a placebo so the concealment is acceptable. In fact, as the main goal of the doctors has shifted from treating one patient's depression successfully to measuring how successful a certain drug is typically, the difference in objective makes the concealment more than just acceptable but also necessary. In the end, the placebo effect is used in clinical trials to determine the worth of the other medicine tested. To treat serious conditions like major depression, it is ideal to produce more improvement than the placebos can provide on their own even in the best case scenario. In studies, medicines are compared to placebos and the extent to which the success of the medicine exceeds the success of the placebo is measured. This measurement is extremely important. If the effect of an antidepressant is indistinguishable from a placebo pill then the medicine is no more helpful than a sugar pill while the antidepressant is more dangerous than a placebo due to the side effects of the former.

Or maybe my grasp on what is considered ethical in medicine nowadays isn't so on point?

Are antidepressants actually more successful than placebos? Survey says, hear more about the implications of the placebo effect on the efficacy of antidepressants in my next blog post.

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Lakoff, Andrew. "The Right Patients for the Drug: Managing the Placebo Effect in Antidepressant Trials." BioSocieties. Web. 25 Apr. 2012. <http://www.palgrave-journals.com/biosoc/journal/v2/n1/full/biosoc20075a.html>.