The Power of the Placebo
Caveat Emptor (Consumer Beware!) is important advice to consumers of products, services, medications, or therapies, including those promoted for use by persons with disabilities. In this column, I will address the issue of the placebo effect in considering whether a product or treatment’s sole benefit is due to positive expectations or whether there is inherent benefit for the specific symptom or problem being targeted. Does a new drug for spasticity in cerebral palsy, for example, improve mobility, increase activity, and promote participation — or, would the same results be seen with a sugar pill or with another treatment (i.e. massage)—plus have the benefit of fewer side-effects?
A placebo is a simulated or otherwise medically ineffectual treatment for a disease or other medical condition intended to deceive the patient. The connotation is negative and the implication is that healthcare providers are trying to trick patients into thinking that their treatment is effective even if the providers believe it may not be or they are unsure. In the past, physicians may have used placebos (usually sugar pills) with the best of intentions, to make patients feel “better” when a real medication, given the potential for bad side effects, was not clearly indicated. For example, drawing from personal history, my father, (a family practitioner) gave me and my siblings sugar “sleeping pills” on Christmas eve to settle us down (create a placebo effect) so we would finally go to sleep. Yes, he was deceiving us, but for a positive benefit with no harm to our physical or mental health. But this is just one meaning of the word placebo.
A more neutral meaning of the word is contained in placebo effect, which occurs when the patient decides a therapy makes him/her better and the belief, not the therapy, makes it so. Skeptics of so-called complementary/alternative medicine (CAM), such as acupuncture or dietary supplements, believe any perceived benefit of these treatments can be attributed to the placebo effect. That is, users of the dietary supplements, for example, improve because they expect to improve, not because the supplements are responsible for the improvement.
To a clinical scientist, placebo has yet another, very precise meaning. The proper way to study a treatment is to compare it to no treatment, using the same outcome measures for both. This type of study is often used to assess the effects and benefits of new medications. One pill contains the drug; another pill that looks exactly the same does not contain the drug. Neither the participants (subjects) in the medication study nor those performing the outcome evaluations know who is taking the drug-containing pill or the look-alike pill (called a placebo). Such a study often produces clear results showing that: patients taking the drug are doing better, or patients taking the drug and those taking the placebo are each better, or that neither the patients taking the drug nor those taking the placebo are better. This procedure is intended to remove the placebo effect bias. Studies that only include persons receiving a treatment are very prone to placebo effect bias. In such studies, one cannot confidently attribute improvement to the treatment because a placebo effect is almost always present. Unfortunately, many treatments that are supposedly “clinically proven” are of this latter type. They cannot be trusted in the same way a properly conducted and studied treatment can be trusted.
The placebo effect, which is an expectation of improvement, is not necessarily bad (depending on the illness or problem being addressed). If someone feels better after a treatment, does it matter whether the treatment was properly evaluated? Furthermore, the placebo effect is not just in the patient’s mind. There is ample evidence that a positive perception of treatment can causes beneficial physiologic changes in the body: e.g. lower blood pressure, release of endorphins (pain relief), and activation of the immune system.
For the scientist studying treatments, use of placebos is not an easy task, especially in treatments not easily masked or simulated. However, it is still essential. Often researchers will compare a new treatment to a standard or usual treatment, as it would not be ethical to stop or withhold treatment that was thought to be helpful, even if the new treatment might prove to be superior. The placebo effect should be recognized and accounted for as precisely as possible in all clinical studies.
How does a consumer of various treatments for cerebral palsy or other disabilities make informed decisions? For example, say a new technologically advance robotic device is promoted as an effective treatment for reducing spasticity (tight muscles) and increasing mobility in cerebral palsy. As with the example of the drug treatment above, consumers should consider whether the use of this device has inherent and lasting functional benefit, related to the specific symptoms (e.g. spasticity) of cerebral palsy. Is the benefit from this therapy superior to other (possibly less expensive) therapies and not just due to expectations of benefit? Can the promoters of this device point to properly conducted studies comparing it to other treatment modalities? Are the non-physiologic benefits (social, emotionally, participatory) of this device different from/superior to those that a person without cerebral palsy would experience?
As in any profession, there are charlatans who are intent on making money without consideration of whether a treatment is truly effective in the long run– after the placebo effect has worn off, (as it inevitably does). Individuals or parents of children with disabilities, such as cerebral palsy, are understandably seeking the best treatments available despite the expense involved. They are, therefore, prone to accepting or willing to try unsubstantiated or improperly evaluated claims of therapeutic benefit from people claiming to be “experts”. In the end, they may be swindled out of a lot of money without gaining any benefits. In some cases, there may be harm.
There are also well-meaning service providers who themselves strongly believe in a therapy for which there is little or no scientific proof of benefit. Their positive view of the therapy will be conveyed to clients and parents who assume that the provider knows best. Doing something (especially if new and glitzy), even without proper proof of efficacy, can appear preferable to same-old therapy routines.
Insurance companies are understandably wary of paying for treatments whose benefits may be due solely to a placebo effect. They look for sound scientific evidence that a treatment has substantial and long-term beneficial effect on function. Again, it is not that the placebo effect is bad, but that it is often transient. A treatment may continue beyond the placebo effect period, producing no further benefit, but utilizing limited therapy insurance benefits.
There are some approaches to therapy for which proof or recognition of the placebo effect is moot and unnecessary. Does one need proof that food is necessary and that a balanced diet is good for you? Likewise, is proof necessary that horseback riding, swimming, or dancing is fun, healthful, and beneficial to the body and psyche? No, unless public programs or health insurance is expected to pay for them as “medical” treatments. In these cases, therapeutic benefit beyond “fun” must be demonstrated. Although one might expect considerable placebo effect from a traditionally recreational activity, such as horse-back riding, advocates of hippotherapy (equine-assisted therapy) have attempted to demonstrate its therapeutic potential with some success using reasonably sound research methodology.1 The same cannot be said for many other proposed treatments. Therefore, as first coined in 1523, Caveat Emptor (Consumer beware!).
There is a strong movement towards greater reliance on an evidence-basis for therapeutic interventions. When confronted with a proposed intervention, it would be very appropriate and wise for parents and consumers to question the evidence-basis for that intervention, whether surgical, medical, therapeutic, or educational.
Sterba, JA. Does horseback riding therapy or therapist-directed hippotherapy rehabilitate children with cerebral palsy? Developmental Medicine and Child Neurology. 2007;49:68-73