Here’s an informative and well done skeptical comic from those geniuses over at PhD comics:

We can glean a number of fascinating things from this comic. First, I bet you didn’t know where the term “mesmerizing” came from. You’re welcome. Second, while medical professionals who practice science-based medicine would argue that the placebo effect is subjective and dependent on the various biases of the patients and researchers, taking a placebo itself has some neurological effects.

In a nutshell, the placebo effect is not some mystical “mind over matter” effect. It is a subjective improvement in non-specific symptoms (like pain, “well-being,” etc.). For example, you can report feeling less pain (a subjective measure) after taking a placebo, even though your ailment persists. In conditions with no subjective ratings, like cancer, there is no placebo effect (i.e., tumor size will not be affected by taking a sugar pill). If we take a cross section of the rapidly building science, it seems that taking a placebo doesn’t have any objective effects on illness, only subjective ones.

So, you can feel better without actually being better. But what the comic above points out is important. Though the placebo effect does nothing objective to your ailment, the expectation of an effect can. For example, taking a placebo pill for blood pressure reduction itself will not affect blood pressure, but the changes in your brain chemistry from taking a supposedly efficacious pill (coming from feelings of relief, an expectation of effect, relaxation, etc.) may in fact help lower it. This is an important distinction: it is the change in your brain chemistry which the placebo treatment elicits that has an effect, not the treatment itself (i.e., a sugar pill did not lower your blood pressure).

But it should be noted that this objective benefit is only in cases where a subjective improvement (brought on by the neurobiological pathways mentioned in the comic) could objectively affect you. When feelings of relaxation and pain relief are meaningless (like in determining the size of a tumor), any objective effects vanish.

What this means is that treatments that do not work beyond placebo, such as homeopathy, acupuncture, reiki, and the like, themselves are not doing anything (the insertion of needles, the laying on of hands, the ingestion of a pill). The expectation of feeling better, the ritual of the treatment, these are the effectors. It also means that, working through placebo alone, these treatments cannot do anything that something else which changes subjective ratings of pain, stress, etc., cannot. Reading a book on a sunny day at the beach, for example, could feasibly produce the same kind of “improvements” that acupuncture does.

Lastly, on a personal note, because of what we know of the placebo effect, I’d like to take a side on the debate that the comic above points out. If we know a treatment like acupuncture or homeopathy does not out-perform placebo, then it is unethical to recommend it to patients. Doctors would not be providing the best care, may be delaying proper treatment, and would in effect be lying to patients about the efficacy of a certain treatment over another. This question is where the main battles in alternative medicine are fought, and is important to keep in mind.