The aim of this study was to examine the relationships among classical conditioning, expectancy, and fear in placebo analgesia and nocebo hyperalgesia. A total of 42 healthy volunteers were randomly assigned to three groups: placebo, nocebo, and control. They received 96 electrical stimuli, preceded by either orange or blue lights. A hidden conditioning procedure, in which participants were not...

Several studies have explored the predictability of placebo and nocebo individual responses by investigating personality factors and expectations of pain decreases and increases. Psychological factors such as optimism, suggestibility, empathy and neuroticism have been linked to placebo effects, while pessimism, anxiety and catastrophizing have been associated to nocebo effects. We aimed to inve...

INTRODUCTION Nocebo-induced algesic responses occurring within clinical contexts present a challenge for health care practitioners working in the field of pain medicine. OBJECTIVES Following the recent research on algesic nocebo effects, the scope of this review is to develop ethically acceptable strategies to help avoid, or at least reduce, nocebo responses within clinical settings. METHOD...

Nocebo hyperalgesia is an increase in subjective pain perception after a patient or subject underwent an inert treatment without any active ingredient. For example, verbal suggestion of increased pain can enhance both pain experience and responses in pain-related cortical brain areas. However, changes in cortical pain responses may be secondary to earlier amplification of incoming pain signals ...

INTRODUCTION Nocebo effects are defined as adverse events related to negative expectations and learning processes that are involved in the modulation of the descending pain pathways. Research over the last couple of decades has illustrated that behavioral, psychoneurobiological and functional changes occur during nocebo-induced pain processing. OBJECTIVES We aimed to review published human an...

OBJECTIVES The present review investigated whether there are systematic sex differences in the placebo and the nocebo effect. METHODS A literature search was conducted in multiple electronic databases. Studies were included if the study compared a group or condition where a placebo was administered to a natural history group or similar cohort. RESULTS Eighteen studies were identified - 12 o...

Recent substantial laboratory and theoretical research hints for different learning mechanisms regulating the formation of placebo and nocebo responses. Moreover, psychological and biological variants may play a role as modulators of learning mechanisms underlying placebo and nocebo responses. In this chapter, we present pioneering and recent human and nonhuman research that has impressively in...

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...

BACKGROUND A "nocebo" effect is defined as troublesome symptoms after the administration of placebo. The aim of this study was to determine characteristics of nocebo responses and related factors. METHODS Patients with a reliable history of drug-induced hypersensitivity reactions subjected to placebo-controlled oral drug provocation tests and reacted to placebo, were consecutively included in...

BACKGROUND This study was designed to compare placebo responses in men and women. METHODS Data for 501 women and 375 men with major depressive disorder treated with placebo from seven investigational randomized double-blind trials comparing fluoxetine with placebo were analyzed. Changes in major depressive disorder symptoms with placebo administration were measured as changes in total Hamilto...