The placebo and nocebo responses in patients with epilepsy

Placebo and nocebo responses in epilepsy have been mainlyinvestigated by meta-analytic approaches aimed to evaluate the extent ofsuch phenomenon in randomized, controlled, clinical trials. These studiesreported placebo response rates (defined as proportion of patients with =50% improvement of seizures compared to baseline observations) rangingfrom 9.9% up to 15.2%. The proportion of patients with adverse events(AEs) and those withdrawing because of intolerable AEs, as index ofnocebo response, were 60.3% and 3.9%, respectively. Moreover, a fullevaluation of specific AEs reported by patients receiving placebo hasbeen performed. A number of factors related to the features of patients(severity of disease), to the study design, or to non-specific factors (suchas year of publication and geographic area), as well as to positive ornegative expectations of patients, caregivers and experimenters have beenshowed to influence placebo and nocebo response in epilepsy. Acharacterization of these factors is crucial for a better interpretation ofstudy results and to improve design of new clinical trials. All recent datawill be presented and discussed in detail.In addition, as neurobiological studies in epilepsy are lacking,putative mechanisms of placebo and nocebo responses in epilepsy will behypothesized and discussed along with possible consequences in clinicalpractice