The Placebo Effect

By: Dr. Marian Eddy-

It is not uncommon for us to hear in a treatment room or around the clinic “why does this work?” or “why do I feel better?”. The most obvious and most common answer is relatively easy to explain and revolves around the biomechanics of an issue. This can include tightness, weakness, postural or strength imbalances, movement pattern dysfunction, overuse, natural healing timelines…and the list can go on. However, sometimes (maybe more often than we’d like to admit), there may be a different mechanism at work. Most of us have heard about a placebo response, and it sometimes comes across with a negative connotation. “Oh that must have just been a placebo”, as if improvement as a result of placebo is all in their head, or is somehow less valuable. Improvement, pain reduction, increases in function…these all seem like pretty darn good things, regardless of what mechanism might be the root cause. So let’s dispel some of that negative thinking and look a bit more into placebos. 

Defined: a placebo is an inert substance or procedure used as a control in clinical trials. In the most classical form, it has been used to confirm efficacy of new drugs and pharmaceutical interventions. In physical medicine, placebo or control groups will receive either “sham” treatment, or at times, no physical intervention at all, but participate in education sessions. It has now been well documented that what could have once been expected to have no result will often provide both subjective and objective positive responses. This placebo effect describes the measurable impact of a placebo. There are a few mechanisms that can cause this effect, including expectation and classical or behavioral conditioning, as well measurable physiological responses.

Much like Pavlov and his dogs, we as humans can be subject to classical conditioning. The expectation that something might be helpful may in part trigger the expected outcome, and we feel a little better. Just the act of seeking help, and actively doing something about it may be a part of the solution. In the world of physical medicine, Messier et al (2021) measured pain and quality of life metrics in participants with knee osteoarthritis after high intensity strength programming, low intensity strength programming, vs control. The control group here didn’t participate in any strength measures, but instead received attention, social interaction with the other participants, education, and seated stretching (colloquially referred to as the coffee and cookies group) over an 18-month period. All pain and quality of life outcomes were similar among groups, with the only statistically significant difference showing in knee extensor strength for the participants in the strength training groups. When compared to other studies with similar methods, the control group in this trial showed a much larger pain control effect. The theory here, is that it wasn’t just the education piece, but the attention to social cognitive strategies to increase adherence that produced a greater effect. This may suggest that the subjective enjoyment, as well as compliance can have a significant effect on pain control and symptom management.

The specific physiologic responses to placebo administration have been thoroughly documented, and the intricacies are far beyond the scope of a blog post by a chiropractor. So two examples in a very summarized manner (in words that I can almost understand):

Leuchter et al (2002) showed a measurable change in metabolism and perfusion in the prefrontal cortex with placebo in depressed subjects. Though not physiologically equivalent to the active drug response it was compared to on functional MRI, there were very few clinical characteristics that could distinguish response to placebo vs the active drug. (Real, objective changes in brain chemistry after placebo – different response than drug, but still a productive response.)

Prossin et al (2022) presents research suggesting that placebo can illicit response of potent nociceptive substances (IL-18) and cascading relationships to endogenous opioid activity. These systems are involved in pain, stress, and mood regulation. (Our own, neurologic and immunologic systems respond and produce pain controlling substances in response to placebo.)

So what? So how do we use this information practically, and how does it change how we approach our own injuries or treatment. Of course, typical means of management have their own specific and desired effect, and we can’t say that if you just believe in something enough, it will work – pain management isn’t Tinkerbell. However, if there are a few concrete things that can be done to maximize improvement, they’re worth discussion. So how can we effectively capitalize on the powerful placebo effect?

  • Get help: Just the act of seeking help, being listened to, and actively doing something viewed as positive for yourself can be productive.
  • Make sure you’re on the same page as your practitioner: It’s important that you understand what the process and goals of treatment are, and that you and your provider are in constant communication to make sure the plan suits your needs and you truly believe it will be successful.
  • Take your “pill”: Do your exercises! Not only will they help mobilize/stabilize/strengthen/desensitize/build confidence around pertinent areas, but creating the routine, knowing that you are doing something to help yourself, expecting improvement, etc…can help that little bit more as well. That being said, if the exercises prescribed by your practitioner are something you don’t understand, or the routine is an hour long and you know walking out of the office that you will never do it – tell them (see above)! Work together to decide what is reasonable and fits your life so that you can reap all of the benefits possible.

The placebo effect can have real, physiological as well as psychological outcomes that may be able to help us get ourselves out of pain, so don’t be afraid to try to use it.


Messier, S., Mihalko, S., Beavers, D., Nicklas, B., DeVita, P., Carr, J., Hunter, D., Lyles, M., Guermazi, A., Bennell, K., & Loeser, R. (2021).  Effect of High-Intensity Strength Training on Knee Pain and Knee Joint Compressive Forces Among Adults with Knee Osteoarthritis. Journal of the American Medical Association. 325(7):646-657.

Leucther, A., Cook, I., Witte, E., Morgan, M., & Abrams, M. (2002). Changes in Brain Function of Depressed Subjects During Treatment with Placebo. American Journal of Psychiatry. 159(1):122-129.

Prossin, A., Koch, A., Campbell, P., Laumet, G., Stohler, C., Dantzer, R., & Zubieta, J. (2022). Effects of placebo administration on immune mechanisms and relationships with central endogenous opioid neurotransmission. Molecular Psychiatry. 27:831-839.