The dominant theories of human placebo effects rely on a notion that consciously perceptible cues, such as verbal information or distinct stimuli in classical conditioning, provide signals that activate placebo effects. However, growing evidence suggest that behavior can be triggered by stimuli presented outside of conscious awareness. Here, we performed two experiments in which the responses t...

Despite the increasing research on placebos in recent times, little is known about the nocebo effect, a phenomenon that is opposite to the placebo effect and whereby expectations of symptom worsening play a crucial role. By studying experimental ischemic arm pain in healthy volunteers and by using a neuropharmacological approach, we found that verbally induced nocebo hyperalgesia was associated...

Conditioning procedures are used in many placebo studies because evidence suggests that conditioning-related placebo responses are usually more robust than those induced by verbal suggestions alone. However, it has not been shown whether there is a causal relation between the number of conditioning trials and the resistance to extinction of placebo and nocebo responses. Here we test the effects...

Herbal medicines are often perceived by the general public as a “soft” alternative to Western Medicine, but the use of these substances can be risky since they can induce nocebo effect [1]. In 1961 Walter Kennedy chosen the term nocebo (Latin for I will harm) as the counterpart of placebo [2]. This term was introduced a few years after Henry Beecher published his paper on the placebo effect [3]...

The nocebo effect is a phenomenon that is opposite to the placebo effect, whereby expectation of a negative outcome may lead to the worsening of a symptom. Thus far, its study has been limited by ethical constraints, particularly in patients, as a nocebo procedure is per se stressful and anxiogenic. It basically consists in delivering verbal suggestions of negative outcomes so that the subject ...

There is growing evidence that placebos are able to influence visual perception. A previous functional magnetic resonance imaging (fMRI) study on the processing of disgust images demonstrated that a 'disgust placebo' (inert pill administered with the verbal suggestion of an anti-nausea medication) reduced visual cortex activity and connectivity. In the present fMRI investigation, we examined co...

While the placebo effect has been studied for a long time, much less is known about its negative counterpart, named the nocebo effect. However, it may be of particular importance because of its impact on the treatment outcomes and public health. We conducted a review on the nocebo effect using PubMed and other databases up to July 2014. The nocebo effect refers by definition to the induction or...

BACKGROUND Nocebo phenomena are common in clinical practice and have recently become a popular topic of research and discussion among basic scientists, clinicians, and ethicists. METHODS We selectively searched the PubMed database for articles published up to December 2011 that contained the key words "nocebo" or "nocebo effect." RESULTS By definition, a nocebo effect is the induction of a ...

INTRODUCTION Placebo and nocebo represent complex and distinct psychoneurobiological phenomena in which behavioural and neurophysiological modifications occur together with the application of a treatment. Despite a better understanding of this topic in the medical field, little is known about their role in physiotherapy. PURPOSE The aim of this review is: a) to elucidate the neurobiology behi...