Neurophysiology and psychobiology of the placebo response.
OBJECTIVE
The placebo literature has substantially increased in 2006 and 2007, and more and more medical and psychological subspecialties have added empirical data to our knowledge.


RESULTS
The theoretical framework of our understanding of the placebo response needs extension to account for findings that cannot be attributed to (Pavlovian) conditioning or suggestions alone. In addition, imaging studies need to address individual responses rather than group means, and to expand beyond experimental pain research. Gender aspects have been demonstrated for the placebo response but still widely ignored, especially in neurophysiological studies. It has been shown that nocebo research needs a methodological and ethical framework that allows its exploration. Finally, analyses of clinical trial data, either as metaanalyses or as reanalyses of trial raw data, may allow us to identify factors that subsequently can be used in experimental work.


CONCLUSIONS
Novel findings will allow better planning of clinical drug trials, better handling of clinical trial data in the future, and finally, may eventually result in improved patient management.
Klosterhalfen
Sibylle
S
Department of Internal Medicine VI/Psychosomatics, University Hospital Tübingen, Germany.
Enck
Paul
P
D001921:Brain / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D002766:Cholecystokinin / Q000502:physiology*; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology; D004298:Dopamine / Q000502:physiology*; D006801:Humans; D015990:Placebo Effect; D049268:Positron-Emission Tomography; D017450:Receptors, Opioid, mu / Q000502:physiology*
D017450:Receptors, Opioid, mu; D002766:Cholecystokinin; D004298:Dopamine