Antipruritic Placebo Effects by Conditioning H1-antihistamine

A narrative review of the placebo effect: historical roots, current applications, and emerging insights

PURPOSE

Placebo is a term to define physiologically inactive compounds used in treatment that causes physical and emotional changes. The placebo effect, driven by expectation and conditioning, plays a significant role in various conditions like pain, depression, and Parkinson's disease, while the nocebo effect can hinder treatment outcomes. Understanding mechanisms such as neuromodulation and genetics has gained importance in modern medicine. This review aims to explore the clinical relevance of placebo responses, particularly in neuropsychiatric disorders, and their potential in personalized medicine. By integrating placebo research into healthcare, it highlights opportunities to enhance treatment efficacy, improve patient well-being, and reduce reliance on pharmacological interventions.

METHODS

A comprehensive literature search was conducted in PubMed, Scopus, and Google Scholar databases. Recent studies were reviewed to evaluate placebo effects, and the variability of the placebo response in neuropsychiatric disorders was summarized.

RESULTS

Placebo effects significantly impact treatment outcomes across various conditions, including Parkinson's disease, depression, pain syndromes, and epilepsy. The mechanisms involve neurobiological and psychological factors, with evidence suggesting that placebo interventions can modulate neurotransmitter activity and improve patient well-being.

CONCLUSION

Integrating placebo research into clinical practice may enhance treatment outcomes, reduce drug dependency, and support personalized medicine by tailoring interventions to individual placebo responsiveness. Understanding placebo and nocebo mechanisms can optimize therapeutic strategies while minimizing unnecessary pharmacological treatments.

Counterconditioning as Treatment to Reduce Nocebo Effects in Persistent Physical Symptoms: Treatment Protocol and Study Design

Persistent physical symptoms have a high prevalence and a large impact for patients and society. To date, treatment effects for these symptoms are often limited. Nocebo effects (i.e., negative outcomes that are not attributable to active treatment components) have a substantial influence on treatment success and can be established via learning through classical conditioning. Therefore, interventions aimed at reducing nocebo effects by means of counterconditioning, in which an alternative association (inhibiting the previous association) is learned, could be a promising method for improving physical symptoms. In experimental studies, counterconditioning has been shown promising in reducing experimentally-induced nocebo effects on pain and itch. Application of counterconditioning procedures to reduce nocebo effects on clinical symptoms has yet to be researched. This paper provides a protocol of a 6-week counterconditioning intervention aimed at reducing nocebo effects and clinical pain in patients with fibromyalgia. A study in patients with fibromyalgia is proposed to examine the feasibility and potential effectiveness of this counterconditioning intervention as a novel treatment method for reducing nocebo effects and generalization to clinical pain symptoms. Results can help design an optimized treatment protocol for reducing nocebo effects, based on the experiences of participants and the first indications of treatment efficacy.

Even when you know it is a placebo, you experience less sadness: First evidence from an experimental open-label placebo investigation

BACKGROUND

Recent studies demonstrate substantial effects of deceptive placebo on experimentally induced sadness, even on autonomic activity. Whether deception is necessary, remains to be elucidated. We investigated the effect of an open-label placebo (OLP) treatment, i.e. an openly administered placebo delivered with a convincing rationale for its sadness-protecting effect.

METHODS

Eighty-four healthy females were randomized to an OLP group or a no-treatment control group. All participants received the same detailed information about the OLP effect, only the OLP group received an OLP nasal spray. Before and after the OLP intervention, participants underwent a sad mood induction procedure combining self-deprecating statements (Velten's method) and sad music. Sadness was assessed by the Positive and Negative Affect Schedule (PANAS-X). Autonomic activity was measured continuously.

RESULTS

Participants in the OLP group reported a significantly attenuated increase in sadness upon mood induction and less sadness after induction compared to the control group (d = 0.79). Regardless of intervention, heart rate decreased during mood inductions with a more pronounced deceleration in the second mood induction.

LIMITATIONS

Generalizability is limited due to the selective sample and the reliance on an experimentally controlled mood induction.

CONCLUSION

OLP treatment had a beneficial effect on perceived sadness, at least at the subjective level. Hence, deception may not necessarily be required for placebos to modulate experienced sad mood. Investigating the beneficial effects of OLP in (sub-)clinical samples would seem a promising and required next step towards a clinical use of placebo-associated positive treatment expectations.

[The effect of treatment expectations on pruritus and skin pain]

Hintergrund

Patientenerwartungen in Bezug auf den Nutzen einer medizinischen Behandlung stellen eine wichtige Determinante für die Placeboantwort dar. Sie können Entwicklung und Verlauf von Erkrankungen sowie Wirksamkeit und Verträglichkeit von Therapien maßgeblich beeinflussen. Die Mechanismen, die diese Placebo- und Noceboeffekte vermitteln, wurden bislang am besten auf dem Gebiet der Placeboanalgesie beschrieben. Aber auch in der Dermatologie findet sich eine zunehmende Evidenz dafür, dass verschiedene Symptome wie Schmerzen an der Haut und Pruritus (Jucken) sowie verschiedene dermatologische Erkrankungen durch die Behandlungserwartungen von Patienten moduliert werden können.

Ziel der Arbeit

Das Ziel dieser Arbeit ist die Darstellung der aktuellen Datenlage in Bezug auf den Einfluss von Erwartungseffekten auf dermatologische Symptome wie Pruritus und Hautschmerzen sowie auf verschiedene dermatologische Erkrankungen. Schließlich soll die Bedeutung dieses Themas für Ärzte, die Patienten mit Hautsymptomen behandeln, vermittelt werden.

Material und Methoden

Es handelt sich um eine narrative Übersichtsarbeit.

Ergebnisse und Diskussion

Eine zunehmende Anzahl von Studien an gesunden Probanden und dermatologischen Patienten zeigt, dass Hautsymptome wie Pruritus und Schmerzen durch die Induktion positiver Erwartungen verringert und durch die Induktion negativer Erwartungen verstärkt werden können. Vorherige Behandlungserfahrungen der Patienten sowie die Qualität und Quantität der Arzt-Patienten-Kommunikation spielen für die Induktion der Behandlungserwartung eine zentrale Rolle.

Schlussfolgerung

Techniken, die darauf abzielen, positive Erwartungseffekte von Patienten mit Hautsymptomen zu maximieren und negative zu minimieren, sollten in die klinische Routine implementiert werden.

Effects of Patients' Expectation in Dermatology: Evidence from Experimental and Clinical Placebo Studies and Implications for Dermatologic Practice and Research

Patients' expectations towards the benefit of a treatment are key determinants of placebo responses and can affect the development and course of medical conditions and the efficacy and tolerability of active medical treatment. The mechanisms mediating these placebo and nocebo effects have been best described in the field of experimental pain and placebo analgesia. However, also in dermatology experimental and clinical studies demonstrate that various skin diseases such as inflammatory dermatoses and allergic reactions can be modulated by patients' expectations. Dermatologists should consider the important modulatory role of patients' expectations on the efficacy and tolerability of specific treatments and the key role of verbal information, patients' prior treatment experiences (associative learning), and the quality and quantity of doctor-patient communication in shaping treatment expectation. As a consequence, techniques aiming at maximizing patients' expectation effects should be implemented into daily clinical routine. By contrast, in clinical studies expectation effects should be maximally controlled and harmonized to improve the "assay sensitivity" to detect new compounds. Further translational studies, also in dermatoses that have not been investigated yet, are needed to better characterize the mechanisms underlying patients' expectation and to gain further insights into potential clinical implications of these effects in dermatologic conditions. Therefore, in this review, we provide a brief overview on the concept of expectation effects on treatment outcome in general, summarize what is already known about this topic for dermatologic diseases, and finally present the relevance of this topic in clinical dermatology.

Placebo and nocebo effects for itch and itch-related immune outcomes: A systematic review of animal and human studies

Placebo and nocebo effects can influence somatic symptoms such as pain. For itch and other dermatological symptoms these effects have been far less investigated. This review systematically integrates evidence from both animal (mainly rodents) and human trials on placebo and nocebo effects in itch, itch-related symptoms and conditions of the skin and mucous membranes, and related immune outcomes (e.g., histamine). Thirty-one animal studies, and fifty-five human studies (k = 21 healthy participants, k = 34 patients) were included. Overall, studies consistently show that placebo and nocebo effects can be induced by various methods (e.g., suggestions, conditioning and social cues), despite high heterogeneity across studies. Effects of suggestions were found consistently across subjective and behavioral parameters (e.g., itch and scratching in humans), whereas conditioning was likely to impact physiological parameters under certain conditions (e.g., conditioning of histamine levels in stressed rodents). Brain areas responsible for itch processing were associated with nocebo effects. Future research may investigate how variations in methods impact placebo and nocebo effects, and whether all symptoms and conditions can be influenced equally.