Evidence for Opioid-Mediated Placebo Analgesia

In 2005, the first direct evidence of opioid-mediated placebo analgesia was published (Zubieta et al., 2005). In vivo receptor-binding techniques using the radiotracer carfentanil, a µ-opioid agonist, were used to show that a placebo procedure activates µ-opioid neurotransmission in the dorsolateral prefrontal cortex, the anterior cingulate cortex, the insula, and the nucleus accumbens (Fig. 4.7). …

Placebo Conditioning by Means of Functional Magnetic Resonance Imaging

Lui et al. (2010) showed dynamic changes in prefrontal areas during placebo conditioning by means of functional magnetic resonance imaging. Brief laser heat stimuli delivered to one foot, either right or left, were preceded by different visual cues, signaling either painful stimuli alone, or painful stimuli accompanied by a sham analgesic procedure. Cues signaling the …

Previous Experience and Analgesia

Previous experience can also influence the magnitude of placebo analgesia. In one study, the intensity of painful stimulation was reduced surreptitiously after placebo administration, so leading subjects to believe that an analgesic treatment was effective (Colloca and Benedetti, 2006) (Fig. 4.2C). Fig. 4.2 C. Variability in magnitude of placebo analgesia. Part (C) shows different degrees …

Verbal Suggestion’s Effect on Analgesia

Today it seems clear that the experimental manipulation used to induce placebo analgesia plays a fundamental role in the magnitude of the response. Among the different manipulations that have been performed, both the type of verbal suggestions and the individual’s previous experience have been found to be important. Verbal suggestions that induce certain expectations of …

Placebo Studies and Ritual Theory

​Experimental research into placebo effects demonstrates that routine biomedical pharmacological and procedural interventions contain significant ritual dimensions. This research also suggests that ritual healing not only represents changes in effect, self-awareness, and self-appraisal of behavioral capacities but involves modulations of symptoms through neurobiological mechanisms. Recent scientific investigations into placebo acupuncture suggest several ways that observations from ritual studies can be verified experimentally. Placebo effects are often described as ‘non-specific’; the analysis presented here suggests that placebo effects are the ‘specific’ effects of healing rituals.

On The Shoulders Of Giants, Part 1: Henry K. Beecher And The Placebo Effect

​But when you look at the distribution of genuine placebo publications in our database (3) (Figure) it was not before the late 1950's when placebo research started to slowly grow, and two milestone papers mark the beginning of it: Henry Beecher’s ever-since-cited paper, “The Powerful Placebo,” of 1955 (4), and Stewart Wolf’s almost completely forgotten, “The Pharmacology of Placebos,” of 1959 (5)