Drugs and Placebos: A Model Design

Ross, Sherman; Krugman, Arnold D.; Lyerly, Samuel B.; Clyde, And Dean J.

doi:10.2466/pr0.1962.10.2.383

Cited by 85 publications

(15 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The first and the most obvious is the small number of studies that provide a test of additivity. The balanced placebo design was first described over 50 years ago (Ross, Krugman, Lyerly, & Clyde, 1962), and several reviews have since highlighted the importance of this design to clarify the assumptions underlying RCTs (Enck, Klosterhalfen, Weimer, et al, 2011; Enck, Klosterhalfen, & Zipfel, 2011; Kirsch, 2000; Kleijnen, de Craen, van Everdingen, & Krol, 1994). It is surprising therefore that so few studies have investigated the assumption of additivity in placebo analgesia—an assumption crucial to the interpretation of RCT outcomes.…”

Section: Implications and Limitationsmentioning

confidence: 99%

Placebo and Active Treatment Additivity in Placebo Analgesia: Research to Date and Future Directions

Coleshill

Sharpe

Colloca

et al. 2018

International Review of Neurobiology

View full text Add to dashboard Cite

Placebo analgesia is a robust experimental and clinical phenomenon. While our understanding of the mechanisms of placebo analgesia has developed rapidly, some central questions remain unanswered. Among the important questions is how placebo anal-gesia interacts with active analgesic effects. It is an assumption underlying double-blind randomized placebo-controlled trials (RCTs) that the true effect of a treatment can be determined by examining the effect of the active treatment arm and subtracting the response in the placebo group (“the assumption of additivity”). However, despite the importance of this assumption for the interpretation of RCTs, it has rarely been formally examined. This article reviews the assumption of additivity in placebo analgesia by examining studies employing factorial designs manipulating both the receipt of an active analgesic and instructions about the treatment being delivered. In reviewing the literature, we identified seven studies that allowed a test of additivity. Of these, four found evidence against additivity, while the remaining three studies found results consistent with additivity. While the limited available data are somewhat mixed, the evidence suggests that at least under some conditions the assumption of additivity does not hold in placebo analgesia. The concordance between mechanisms of the active analgesic and placebo analgesia may influence whether additivity occurs or not. However, more research using factorial designs is needed to disentangle the relationship between placebo analgesia and the active effect of analgesic treatments.

show abstract

Section: Implications and Limitationsmentioning

confidence: 99%

Placebo and Active Treatment Additivity in Placebo Analgesia: Research to Date and Future Directions

Coleshill

Sharpe

Colloca

et al. 2018

International Review of Neurobiology

View full text Add to dashboard Cite

show abstract

“…A very useful design for the control of factors influencing the placebo response is the "balanced placebo design" 50] (for detailed discussion see [4] ). The original design includes a minimum of four groups, an active drug group and it's control, placebo, and two more groups, which are varied according to factors influencing the placebo response, such as beliefs induced by instructions (Table 1), doctors attention, study visits, medication regimen etc.…”

Section: Methodological Aspects and Implications For Clinical Trialsmentioning

confidence: 99%

Placebo responses in patients with gastrointestinal disorders

Klosterhalfen¹,

Enck²

2007

WJG

View full text Add to dashboard Cite

Over the last several years there has been a growing interest in placebo, not only as an inert control in clinical trials, but also in the placebo effect as a group effect as well as a reaction in individual subjects. Methodological factors such as regression to the mean and natural history of the disease play a role in the evaluation of a possible placebo effect. In this report, we discuss several factors including Pavlovian conditioning, beliefs outcome, expectations, and other factors as potential mediators of the placebo response. Placebo effects are common in gastrointestinal diseases and there seems to be no clear difference between placebo effects in functional gastrointestinal diseases (functional dyspepsia and irritable bowel syndrome) and organic gastrointestinal disease (duodenal ulcer and inflammatory bowel disease).

show abstract

“…(132), in a psychological study of the effects of d-amphetamine on mood and psychomotor performance in elderly veterans, have attempted an experimental design in which the placebo and drug effects can easily be sorted out. It is interesting to note that the drug group in this study showed unpleasant affective response and impaired motor performance, while the placebo group showed positive affective response.…”

Section: Other Centrally Acting Drugsmentioning

confidence: 99%

Some Aspects of Central Nervous Pharmacology

Toman¹

1963

Annu. Rev. Pharmacol.

View full text Add to dashboard Cite

Drugs and Placebos: A Model Design

Cited by 85 publications

References 5 publications

Placebo and Active Treatment Additivity in Placebo Analgesia: Research to Date and Future Directions

Placebo and Active Treatment Additivity in Placebo Analgesia: Research to Date and Future Directions

Placebo responses in patients with gastrointestinal disorders

Some Aspects of Central Nervous Pharmacology

Contact Info

Product

Resources

About