Ben Colagiuri
Senior Lecturer, University of Sydney

Using learning mechanisms to inhibit the development of nocebo nausea

Nausea is a prevalent and debilitating side effect of many medical treatments. While pharmacological factors undoubtedly contribute to nausea, there is increasing evidence that the nocebo effect also plays a critical role in the development of nausea. In particular, the formation of associations between the treatment context and the pharmacological agent can lead the treatment context to exacerbate or even induce nausea in and of itself via learning mechanisms. To attempt to combat this, we tested whether pre-exposure to the treatment context prior to treatment could reduce nocebo nausea via latent inhibition. Across two experiments, healthy volunteers underwent nocebo nausea conditioning with Galvanic Vestibular Stimulation (GVS). Critically, some of the participants were randomized to receive pre-exposure to placebo GVS prior to their conditioning in either a deceptive (Experiment 1) or open manner (Experiment 2). In Experiment 1 there was clear evidence of conditioned nocebo nausea that was entirely blocked by pre-exposure to placebo GVS, indicating a latent inhibition effect. In Experiment 2, we replicated the latent inhibition effect for deceptive pre-exposure and found that open pre-exposure was just as successful at blocking the development of nocebo nausea as deceptive pre-exposure. As such, pre-exposure may be an effective method of reducing the development of nocebo nausea and other nocebo effects to reduce the overall burden that side effects cause patients. To this end, the fact that open pre-exposure is as effective as deceptive pre-exposure indicates that latent inhibition can be deployed ethically in clinical practice without violating informed consent.


Dr. Ben Colagiuri received his PhD in Psychology from the University of Sydney, Australia in 2010. He currently holds a Senior Lectureship and Australian Research Council Discovery Early Career Research Award in the same School. His research aims to understand how expectancies shape human behavior, with a specific interest in placebo and nocebo effects. To date, he has developed a number of novel experimental models to uncover the mechanisms of the placebo and nocebo effect for pain, sleep, nausea, and other conditions. He has published over 40 scientific papers and received state and national recognition for his research, including the Australian Psychological Society Early Career Research Award 2014. His current research is exploring how the placebo effect can be used to improve clinical trial design and clinical practice, with the ultimate aim of enhancing patients’ health and wellbeing.