Placebo and nocebo responses in drug trials of XXXX .

@entity1 @entity410 @entity1625 @entity302
UNASSIGNED: Placebo response can be defined as any therapeutic change on placebo, while the nocebo response is any ill effect during placebo exposure. Several meta-analytic approaches have investigated the extent of placebo response in randomized, placebo-controlled, clinical trials of @entity1625 . Placebo response rates (proportion of @entity1 with >= 50% improvement of @entity410 versus baseline) ranging from 9.9% up to 15.2% have been reported. Interestingly, a sham response of 15.8% has been noted in trials of transcranial magnetic stimulation. Recently, nocebo response rates of 60.3% and 3.9% were noted, which were defined as the proportion of @entity1 with adverse events (AEs) and those withdrawing because of intolerable AEs, respectively. Factors which were found to influence placebo response were as follows: the year of publication (with more recent studies showing higher rates of placebo response), some clinical characteristics of recruited @entity1 (lower placebo response rates with a history of 7 or more prior lifetime AEDs, a high baseline @entity410 frequency, prior @entity302 surgery, and higher age at diagnosis), trial design and statistical analysis, and whether studies have been conducted in @entity1 or adults. Furthermore, placebo and nocebo rates were correlated with respective @entity410 outcome and adverse events of the experimental AED. Several mechanisms of placebo and nocebo responses are discussed. Specifically, the role of positive or negative expectations of @entity1 and of investigators may influence the placebo and the nocebo response. Finally, recommendations are given on how to address placebo and nocebo responses in clinical practice.
