Cognitive Schemas in Placebo and Nocebo Responding: Role of Autobiographical Memories and Expectations.
OBJECTIVE
Placebo effects are presumed to be based on one's expectations and previous experience with regard to a specific treatment. The purpose of this study was to investigate the role of the specificity and valence of memories and expectations with regard to itch in experimentally induced placebo and nocebo itch responses. It was expected that cognitive schemas with more general and more negative memories and expectations with regard to itch contribute to less placebo itch responding.


METHODS
Validated memory tasks (ie, the Autobiographical Memory Test and the Self-referential Endorsement and Recall Task) and expectation tasks (ie, Future Event Task and the Self-referential Endorsement and Recall Task) were modified for physical symptoms, including itch. Specificity and valence of memories and expectations were assessed prior to a placebo experiment in which expectations regarding electrical itch stimuli were induced in healthy participants.


RESULTS
Participants who were more specific in their memories regarding itch and who had lesser negative itch-related expectations for the future were more likely to be placebo itch responders. There were no significant differences in effects between the nocebo responders and nonresponders.


CONCLUSIONS
The adapted tasks for assessing cognitive (memory and expectations) schemas on itch seem promising in explaining interindividual differences in placebo itch responding. Future research should investigate whether similar mechanisms apply to patients with chronic itch. This knowledge can be used for identifying patients who will benefit most from the placebo component of a treatment.
Health, Medical and Neuropsychology Unit, Institute of Psychology, Leiden University, Leiden, the Netherlands; Leiden Institute for Brain and Cognition, Leiden University, Leiden, the Netherlands. Electronic address: d.bartels@fsw.leidnuniv.nl.
Danielle J P
DJP
Bartels
Health, Medical and Neuropsychology Unit, Institute of Psychology, Leiden University, Leiden, the Netherlands; Leiden Institute for Brain and Cognition, Leiden University, Leiden, the Netherlands; Department of Psychiatry, Leiden University Medical Center, Leiden, the Netherlands.
Antoinette I M
AIM
van Laarhoven
Scientific Institute for Quality of Healthcare, Radboud University Medical Center, Nijmegen, the Netherlands.
Naomi
N
Heijmans
Centre for the Psychology of Learning and Experimental Psychopathology, University of Leuven, Leuven, Belgium.
Dirk
D
Hermans
Centre for the Psychology of Learning and Experimental Psychopathology, University of Leuven, Leuven, Belgium; Department of Applied Psychology, Thomas More University College, Antwerp, Belgium.
Elise
E
Debeer
Department of Dermatology, Radboud University Medical Center, Nijmegen, the Netherlands.
Peter C M
PCM
van de Kerkhof
Health, Medical and Neuropsychology Unit, Institute of Psychology, Leiden University, Leiden, the Netherlands; Leiden Institute for Brain and Cognition, Leiden University, Leiden, the Netherlands; Department of Psychiatry, Leiden University Medical Center, Leiden, the Netherlands; Department of Medical Psychology, Radboud University Medical Center, Nijmegen, the Netherlands.
Andrea W M
AWM
Evers
D000328:Adult; D003071:Cognition; D005260:Female; D006801:Humans; D008297:Male; D061212:Memory, Episodic; D064786:Nocebo Effect; D015990:Placebo Effect; D011537:Pruritus / Q000523:psychology*; D055815:Young Adult
autobiographical memory; cognitive bias; future expectations; itch; placebo effect