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Placebo Effect

(From: Buck, T., Sales, A., Kampfe, C., McAllen, L., & Archembault, C. (2005). A study of worldviews and use of complementary and alternative medicine. In R. Morris (Ed.), Disability Research and Policy: Current Perspectives. Mahwah, NY: Lawrence Erlbaum & Associates.)

The term “placebo effect” often brings up a negative connotation in health care due to its role in research and association with hypochondriasis. Positive results from use of placebo will “verify” beliefs that symptoms that “should” not exist truly are “all in a person’s mind”. Placebo effect, as defined by Shapiro (1961), follows:

…any therapeutic procedure (or that component of any therapeutic procedure) which is given deliberately to have an effect, or unknowingly has an effect on a patient, symptom, syndrome, or disease, but is objectively without specific activity for the condition being treated. (In Noon, 1999, p. 133)

Recruiting the positive benefits of placebo effect has been used in medicine throughout the centuries (Kapp, 1982; Straus & von Ammon Cavanaugh, 1996). Research by Schwartz, Soumerai, and Avorn (1989) revealed that among 110 physicians studied, 24% intentionally prescribed drugs for their placebo effect. This was not surprising due to research studies on placebo effect and pharmaceutical pain management that reveal some 30-40% of pain patients responded to placebo treatment and that 50-60% of pain symptom relief can be attributed to placebo effect (Noon, 1999). Additional research reveals that placebos are clinically beneficial in 60-90% of diseases (Benson & Friedman, 1996). Some characteristics of placebos that mimic active drug intervention are as follows: (1) direction of effect: a placebo will mimic an active treatment by increasing or decreasing the effect of the active treatment in the same direction; (2) equivalence of strength: the placebo will mimic the strength of the active treatment such as a mild analgesic versus a strong analgesic; (3) side effects: placebos have been found to mimic side effects of active treatments such as nausea, headaches, etc.; (4) time course: the length of time of active treatment effect will be mimicked by a placebo; and (5) ‘therapeutic window’: with regard to dosage, the range of effectiveness will be mimicked by a placebo (Ross & Olsen, 1981). Additionally, research shows that placebo effectiveness can be found when the following components are presented: patient belief and expectancy in the placebo, practitioner belief and expectancy in the placebo, a good therapeutic alliance between the patient and practitioner (Benson & Friedman, 1996).

Noon (1999) described several theories that have been used to explain placebo effect. One theory is natural history that bases placebo effect on the naturally occurring ability of the body/mind to heal itself. An example of this is the body’s natural ability to overcome a viral infection. Antibiotics are often prescribed for viral infections but have no actual clinical effect on viruses. An assumption about placebo effect in such situations is that the antibiotics might be believed to be the healing agent for the virus, when in fact it was the body’s natural immune system that was able to overcome the virus. Another theory attributes placebo effect to anxiety reduction: the effects of reduced anxiety on symptom relief. Finally, expectancy theory explains placebo effect as the generation of beliefs that lead to expectations, and that it is the beliefs and expectations that contribute to the healing process.

Noon (1999) also indicated that when anxiety reduction and expectancy theories are combined, they can explain the gain of confidence in an intervention through expectation that in turn reduces anxiety, thus reducing symptoms. This combined theory can also be viewed in terms of the biopsychosocial model of medicine: that the central nervous system responds to cognitive processes and emotional responses that are guided by the cultural context in which they take place (Noon, 1999). Therefore, an important guiding force in the course of healing is the psychophysiological response to underlying beliefs. Pepper’s World Hypotheses represent worldviews that are the underlying beliefs and expectancies that drive cognitive processes in spite of the cultural context in which they take place.”

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