Placebo Effect: You Probably Shouldn’t Know This, But…

This is one of those papers where the abstract doesn’t quite cut it, and the whole paper was a fascinating read. I got thinking about it after reading my favorite paper on acupuncture, “Acupuncture is Theatrical Placebo” and I have since caught myself using the term “theatrical placebo” on the reg. That got me wondering and talking about the placebo effect and thinking the more theatrical the treatment the more effect you might get. Such that placebo shots would be more effective than placebo pills, and placebo surgery better still. It turns out, that’s pretty much the case but the details are fascinating. See my comments below the abstract for details.

The “placebo” response in osteoarthritis and its implications for clinical practice. Doherty M, Dieppe P. Osteoarthritis Cartilage. 2009 Oct;17(10):1255-62. Apr 17. [FREE FULL TEXT AVAILABLE]

Abstract
Many observations support a major biological effect from the way in which people interpret the meaning of each component of their medical experience and the context in which this occurs. A recent systematic review of randomised controlled trials in osteoarthritis has demonstrated that the effect size of “placebo” is substantial and is usually greater than that obtained from the specific effect of an individual treatment. In the context of a randomised controlled trial, such a large placebo or “meaning” response is considered a nuisance, but in the context of clinical practice the optimisation of such meaning and contextual responses, through enhanced “care”, could greatly benefit people who suffer from osteoarthritis.

My comments:

As mentioned above the abstract doesn’t do this paper justice, and the full text is well worth a read, going well beyond the treatment arthritis. Reported findings include:

  1. With regards to osteoarthritis the effect size of the placebo (0.5-0.7) was much larger than that achieved with analgesic and anti-inflammatory drugs (0.2-0.3).
  2. Brand name placebo pills work better than generic placebo pills.
  3. Perceived price matters. Patients told their pills are expensive get a better effect than if they are told they got them discounted.
  4. Knowing, and seeing the intervention happening helps. Morphine administered directly into a PIC line led to faster pain relief than if it were concealed. Also open discontinuation of morphine administration resulted in a rapid return of pain, while concealed discontinuation did not.
  5. Yes, the more invasive the procedure, the better the placebo. Injections work better than placebo pills, and placebo surgery works better still.
  6. More placebo pills, injections, needles work better than fewer. Psychologically, acupuncture/dry needling which frequently uses a lot of needles would appear to have a has a lot going for it, though it’s unfortunate if you end up with a pneumothorax.
  7. Expectations matter a lot. If subjects are told what to expect, they’ll get more of that. They found ipecac (used to induce vomiting) can reduce nausea if subjects are told that’s what it does.
  8. A ‘new’ fake treatment works better than one where the treatment is established.
  9. Placebo response isn’t entirely psychological. There is evidence that placebo effects cause a real increase in endogenous opioids. (aka endorphins). This was one of the more interesting aspects of the paper to me and I’ll probably look up the references to see how much endorphin response there was from placebo treatments, how that relates to exercise, or other treatments (like TENS) reported increase endorphins to know if one increases them more than another. I’m also curious as to whether or not the more powerful placebo effects work all or in part by increased endorphin response.
  10. The nicer/more natural the environment/view (e.g. being able to look out the window and see trees) the better the outcomes of treatment.
  11. For irritable bowel syndrome (IBS) no treatment/waiting list was 28% effective, sham acupuncture (kind an oxymoron) with limited practitioner interaction was 44% effective, while sham acupuncture applied with positive practitioner intervention, with “warmth, attention and confidence” was 62% effective.
  12. An exorcism maybe works better than an aspirin if the patient really believes their possessed.
  13. If the provider is optimistic about the treatment, it improves outcomes. Provider pessimism does the opposite.
  14. A positive consultation for which the patient was given a confident diagnosis and told things would improve led to better (64% improvement) compared to a negative/indefinite consultation (39%) for which the doctor said “I cannot be certain what is the matter with you.” They said receiving a prescription made no difference. This overlaps with the optimism, but it seems a confident diagnosis matters. This is something I have noticed improves with experience and as important continued reading of the medical literature. Diagnosis do become more exact, and you sound better talking about it.

The good news from all this is that most of the above benefits are not exclusive to sham interventions but generally come along free with real treatment. I could comment on this paper for hours, but for the most part it reminds of the review paper on optimism I blogged on. As such I think “real” treatment provided positively, with caring and confidence is the best of all worlds. I think using known or suspected placebo treatments is what practitioners do only if they ignorant of better ideas and/or  (more often the case) fooled themselves.

As always, if you have any further questions or need for clarifications, please don’t hesitate to ask. Being aware that some of my blog ideas are contentious and occasionally a bit out of the field of my expertise, I encourage my readers to come forth with any questions/comments that are of interest or concern. Your comments are valued and welcomed.

Chad Reilly is a licensed physical therapist, located in North Phoenix, practicing science based medicine with treatment protocols unique and effective enough to proudly serve patients from Phoenix, Scottsdale, Mesa, Chandler, Tempe, Peoria, and Glendale.

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