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The placebo effect, defined as symptom improvement following delivery of an inert substance, is often cast in a negative light, as a confounder during research and indication of malingering among certain patients.
However, studies indicate just the opposite: placebo can improve symptoms of pain and discomfort, due to specific neurochemical responses that occur when inert substances are delivered with the appropriate environmental cues (Goffaux et al., 2010).
In fact, imaging studies revealed that placebo analgesia triggers the release of endogenous opioids (Goffaux et al., 2010), that bind with the brain’s opioid receptors in a similar matter to exogenous opioid medications.
As applied to clinical settings, this suggests that a positive therapeutic relationship does more than improve patient satisfaction, it can also increase the efficacy of whatever treatments the healthcare provider is delivering.
Researchers from the University of Montreal developed a model of the placebo effect as it applies to analgesia (Goffaux et al., 2010). This model divides the placebo effect into three phases: induction, psychophysiological mediators and actualization.
Induction includes the therapeutic message and alliance; method of administration, assessment of side effects, and follow-up; sociocultural factors, patient history, beliefs and values.
Psychophysiological mediators include conditioning (environmental cues), cognitive factors, patient motivation and emotions that trigger specific neurochemical responses triggered by the production of endorphins, dopamine and other neurotransmitters, leading to activation of the descending inhibitory pain system within the central nervous system (CNS).
Actualization of effects is the patient’s response, modulated by the subjective pain experience, emotions, symptom relief and general quality of life as well as objective clinical indicators assessing nociceptive activity.
Certain types of placebos tend to be more effective than others. For example, suggestive strategies such as delivering two pills rather than one can increase therapeutic response to placebo. Similarly, more invasive procedures (saline intravenously delivered to a control group) may be more suggestive of treatment efficacy.
Article authors suggest an important consequence of their research, as applies to the common clinical practice of starting with low doses of pain medications and ramping up.
Patients who have inadequate response to the initial low dose develop negative expectations that can impact the efficacy of higher doses (Goffaux et al., 2010). This supports the idea of helping the patient ‘get ahead of the pain,’ which can have significant consequences for individuals at risk of developing chronic pain symptoms.
Cast in this light, the placebo effect becomes a win/win. It is effective, inexpensive, and cast within the proper context, has little risk for negative physiological side effects.
When used together with the appropriate active treatment, placebo analgesia becomes a powerful tool by considering both the physical and emotional aspects of the pain experience.
Goffaux, P., Léonard, G., Marchand, S., & Rainville, P. (2010). Placebo analgesia. Pharmacology of Pain. IASP Press, Seattle, 451-473.