The Placebo Effect

 

The placebo effect is the treatment effect that is not induced by a specific treatment such as pharmacological substance. We are interested in undersatnding the neural underpinnings of the placebo effect. We first focused on placebo analgesia in our placebo research since the placebo effect has previously been best described for pain in a long series of experimental studies. We were first to describe the processes in the human brain underlying placebo analgesia (Petrovic et al Science 2002), and showed that two regions were involved in the placebo response: the orbitofrontal cortex (Obfc) and the rostral anterior cingulate cortex (rACC). This study opened a new research direction in cognitive neuroscience and it has been cited over 700 times.

 

 Our group has also generalized the ideas of placebo analgesia to emotional processing and perception (Petrovic et al Neuron 2005). This experimental model is important since there it has been a fierece debate about the placebo effect in antidepressive teratment - but virtually no experimetal studies on this topic in cognitive neuroscience. In that study we discovered that similar prefrontal systems (Obfc and rACC) were involved as in placebo analgesia. We also built a theoretical model of the placebo effect that builds on general information processing of expectations, and showed evidence in favour of this model (Petrovic et al Pain 2010). We generalized this idea further by showing “placebo-like” modulation of a visual illusion (Sterzer et al Current Biology 2008; Schmack Journal of Neuroscience 2013). Finally, we have studied expectation effects in the brains of treating doctors (Jensen et al Molecular Psychiatry 2014) since it has been suggested that the the social interaction between the treater and the patient is the most signiciant aspects of the placebo effect.