Placebo Effects in the Neuroendocrine System: Conditioning of the Oxytocin Responses

Skvortsova, Aleksandrina; Veldhuijzen, Dieuwke S.; Pacheco-López, Gustavo; Bakermans-Kranenburg, Marian; IJzendoorn, Marinus van; Smeets, Monique A. M.; Wilderjans, Tom F.; Dahan, Albert; Bergh, Omer Van den; Chavannes, Niels H.; Wee, Nic J.A. van der; Grewen, Karen; Middendorp, Henriët van; Evers, Andrea W M

doi:10.1097/psy.0000000000000759

Cited by 4 publications

(1 citation statement)

References 61 publications

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“…This aroma oil has previously been used successfully in a study on classical conditioning of oxytocin ( 28 ) by our study group, and, mixed with peppermint oils, in previous research on conditioning of insulin responses ( 7 , 9 ). This smell was rated as pleasant but unfamiliar in previous research ( 28 ). Commercially available felt-tip pens were filled with rosewood oil used as a CS.…”

Section: Methodsmentioning

confidence: 99%

Influencing the Insulin System by Placebo Effects in Patients With Diabetes Type 2 and Healthy Controls: A Randomized Controlled Trial

et al. 2023

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Objective The objective of this study was to investigate whether placebo effect induced by pharmacological conditioning with intranasal insulin can affect glucose, insulin, C-peptide, hunger, and memory in patients with diabetes type 2 and healthy controls. Methods Placebo effect was induced by pharmacological conditioning. Thirty-two older patients (mean age = 68.3 years) with diabetes type 2 and age- and sex-matched thirty-two healthy older adults (mean age = 67.8 years) were randomly assigned to a conditioned or a control group. On day 1, conditioned group received six administrations of intranasal insulin with a conditioned stimulus (CS; smell of rosewood oil), whereas the control group received a placebo with the CS. On day 2, both groups received a placebo spray with the CS. Glucose, insulin, and C-peptide were repeatedly measured in blood. Hunger and memory were assessed with validated measures. Results Intranasal insulin stabilized dropping glucose levels in patients (B = 0.03, SE = 0.02, p = .027) and healthy men (B = 0.046, SE = 0.02, p = .021), and decreased C-peptide levels in healthy controls (B = 0.01, SE = 0.001, p = .008). Conditioning also prevented the drop of glucose levels but only in men (both healthy and patients; B = 0.001, SE = 0.0003, p = .024). Conditioning significantly decreased hunger in healthy participants (B = 0.31, SE = 0.09, p < .001). No effects were found on other measures. Conclusions Placebo effect induced by conditioning with intranasal insulin modifies blood glucose levels and decreases hunger in older adults, but its effects depend on health status and sex. Insulin conditioning might be beneficial for groups suffering from intensive hunger but seems not be particularly suitable for blood glucose reduction. Trial Registration Netherlands Trial Register, NL7783 (https://www.trialregister.nl/trial/7783).

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Section: Methodsmentioning

confidence: 99%

Influencing the Insulin System by Placebo Effects in Patients With Diabetes Type 2 and Healthy Controls: A Randomized Controlled Trial

et al. 2023

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Conditioning cortisol in healthy young women – A randomized controlled trial

Tekampe

Middendorp

Biermasz

et al. 2021

Psychoneuroendocrinology

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A Systematic Review of the Role of Oxytocin, Cortisol, and Testosterone in Facial Emotional Processing

Romero‐Martínez

Sarrate-Costa

Moya-Albiol

2021

Biology

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A topic of interest is the way decoding and interpreting facial emotional expressions can lead to mutual understanding. Facial emotional expression is a basic source of information that guarantees the functioning of other higher cognitive processes (e.g., empathy, cooperativity, prosociality, or decision-making, among others). In this regard, hormones such as oxytocin, cortisol, and/or testosterone have been found to be important in modifying facial emotion processing. In fact, brain structures that participate in facial emotion processing have been shown to be rich in receptors for these hormones. Nonetheless, much of this research has been based on correlational designs. In recent years, a growing number of researchers have tried to carry out controlled laboratory manipulation of these hormones by administering synthetic forms of these hormones. The main objective of this study was to carry out a systematic review of studies that assess whether manipulation of these three hormones effectively promotes significant alterations in facial emotional processing. To carry out this review, PRISMA quality criteria for reviews were followed, using the following digital databases: PsycINFO, PubMed, Dialnet, Psicodoc, Web of Knowledge, and the Cochrane Library, and focusing on manuscripts with a robust research design (e.g., randomized, single- or double-blind, and/or placebo-controlled) to increase the value of this systematic review. An initial identification of 6340 abstracts and retrieval of 910 full texts led to the final inclusion of 101 papers that met all the inclusion criteria. Only about 18% of the manuscripts included reported a direct effect of hormone manipulation. In fact, emotional accuracy seemed to be enhanced after oxytocin increases, but it diminished when cortisol and/or testosterone increased. Nonetheless, when emotional valence and participants’ gender were included, hormonal manipulation reached significance (in around 53% of the articles). In fact, these studies offered a heterogeneous pattern in the way these hormones altered speed processing, attention, and memory. This study reinforces the idea that these hormones are important, but not the main modulators of facial emotion processing. As our comprehension of hormonal effects on emotional processing improves, the potential to design good treatments to improve this ability will be greater.

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Placebo Effects in the Neuroendocrine System: Conditioning of the Oxytocin Responses

Cited by 4 publications

References 61 publications

Influencing the Insulin System by Placebo Effects in Patients With Diabetes Type 2 and Healthy Controls: A Randomized Controlled Trial

Influencing the Insulin System by Placebo Effects in Patients With Diabetes Type 2 and Healthy Controls: A Randomized Controlled Trial

Conditioning cortisol in healthy young women – A randomized controlled trial

A Systematic Review of the Role of Oxytocin, Cortisol, and Testosterone in Facial Emotional Processing

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