Placebo analgesia: cognitive influences on therapeutic outcome

Abstract

The therapeutic response to a drug treatment is a mixture of direct pharmacological action and placebo effect. Therefore, harnessing the positive aspects of the placebo effect and reducing the negative ones could potentially benefit the patient. This article is aimed at providing an overview for clinicians of the importance of contextual psychosocial variables in determining treatment response, and the specific focus is on determinants of the placebo response. A better understanding of the physiological, psychological, and social mechanisms of placebo may aid in predicting which contexts have the greatest potential for inducing positive treatment responses. We examine the evidence for the role of psychological traits, including optimism, pessimism, and the effect of patient expectations on therapeutic outcome. We discuss the importance of the patient-practitioner relationship and how this can be used to enhance the placebo effect, and we consider the ethical challenges of using placebos in clinical practice.

Naproxen Effects on Brain Response to Painful Pressure Stimulation in Patients with Knee Osteoarthritis: A Double-blind, Randomized, Placebo-controlled, Single-dose Study

“…In our empirical clinical study, we tested just the outcome of the placebo effect that showed response attenuation in a variety of brain structures related to pain perception. Relevantly, placebo-related changes involved the dorsal lateral prefrontal cortex, which is one of the key areas mediating the top-down effects of placebo 40,41,42,43,44 . Compared with placebo, naproxen showed a stronger effect on core regions of the pain-processing system.…”

“…Few specific imaging studies have been done in patients with chronic OA, even though the placebo effect is notable in this clinical condition 38,39 . Experimental work has shown that placebo analgesia is mediated by the activation of descending, mostly opioids, pain modulatory circuits with the implication of the prefrontal cortex, anterior cingulate cortex, and deep elements like the PAG and amygdala 40,41,42,43,44 . As a result, the brain response to nociceptive stimulation is attenuated 3,45 .…”

Predictive mechanisms linking brain opioids to chronic pain vulnerability and resilience

“…For example, placebo analgesia, thought to be mediated by conscious or unconscious (e.g . conditioned) expectations (Watson et al, ), is opioid‐mediated (Benedetti et al, ). Furthermore, behavioural and neuroimaging studies show that the analgesic effect of synthetic opiates during experimental pain is blocked by negative suggestion (Bingel et al, ).…”

A pilot study of myofascial release therapy compared to Swedish massage in Fibromyalgia

“…As the current study was parallel in design, it is less likely that Hawthorne, placebo effect or therapeutic relationship influenced the data. The placebo response is a biologically active process known to reduce pain and often encouraged in clinical practice (Watson et al, 2012). However, it may confound the mechanism of action of therapies when studies do not compare two active modalities in a parallel fashion.…”