Entry Homeopathy and Psychological Therapies Davide Donelli * and Michele Antonelli AUSL-IRCCS Reggio Emilia, 42122 Reggio Emilia, Italy; [email protected] * Correspondence: [email protected] Definition: Homeopathy is a popular, although highly debated, medicinal practice based on the administration of remedies in which active substances are so diluted that no detectable trace of them remains in the final product. This hypothesis paper aims to outline a possible reinterpreta- tion of homeopathy in the light of psychological therapies in order to improve its clinical safety and sustainability. Keywords: homeopathy; psychology; reinterpretation; hypothesis 1. Introduction Homeopathy is a popular, although highly debated, medicinal practice. In Italy, for ex- ample, it is estimated that, even if with a slightly declining trend, around 4.1% of the entire population (almost 2.5 million people) occasionally or regularly seeks homeopathic care, and these data, collected in 2013, suggest that homeopathy is the most used Complemen- tary and Alternative Medicine (CAM) by Italians [1]. Epidemiological studies aimed to assess the worldwide prevalence of homeopathy use have reported similar data for other high-income countries [2]. Homeopathy was first invented by the German doctor Samuel Hahnemann (1755–1843), and it is based on the administration of remedies in which active substances are so diluted that no detectable trace of them remains in the final product [3]. In his empirical studies, Citation: Donelli, D.; Antonelli, M. Hahnemann reported that the self-administration of a common antimalarial medicinal Homeopathy and Psychological Ther- plant (Cinchona) resulted in the occurrence of the same symptoms of malaria, but to a Encyclopedia 2021 1 apies. , , 57–64. milder degree [4]. This led him to cast the foundations of a new medicinal system called https://dx.doi.org/10.3390/ “homeo-pathy”, a noun that originates from the combination of two Greek terms: “homeo-” encyclopedia1010008 (from “homoios”, a prefix standing for “same”, “like”) and “-pathy” (from “patheia”, or “suffering”, a suffix usually indicating all diseases) [5]. Hahnemann stated that the Academic Editor: Raffaele Barretta Received: 17 October 2020 proper disease remedy has to be chosen by the homeopathic practitioner on the basis of Accepted: 18 December 2020 the principle summarized by a Latin expression: “similia similibus curantur” (literally, Published: 23 December 2020 like cures like) [3]. In other words, a therapeutic remedy is recommended for a given illness if pharmacological doses of the original substance would theoretically produce the Publisher’s Note: MDPI stays neu- same effects on the body as the disease symptoms. The preparation of a homeopathic tral with regard to jurisdictional claims remedy implies a serial high dilution of the original substance, along with some mechanical in published maps and institutional “succussions” or shakes (a process sometimes called “dynamization” or “potentiation”, affiliations. which is believed to boost the efficacy of the remedy). Every homeopathic product is usually labelled with a Latin name (for example: Aconitum napellus) indicating the original principle which has undergone serial dilutions. Latin is used because of historical traditions and because all physicians worldwide can more easily and unequivocally understand it [6]. Copyright: © 2020 by the authors. Li- Along with their name, homeopathic products often carry a brief description of “how censee MDPI, Basel, Switzerland. This much” they have been diluted: For example, “30 CH” means that the original principle has article is an open access article distributed been diluted by a factor of 100 (usually in a hydroalcoholic solution) for 30 times. More under the terms and conditions of the Creative Commons Attribution (CC BY) precisely, “CH” stands for “Hahnemann’s Centesimal [dilution]”, thus referring to the license (https://creativecommons.org/ method for preparation of homeopathic remedies invented by the German doctor [6]. Com- licenses/by/4.0/). mon formulations of homeopathic products found in the market usually include sucrose- Encyclopedia 2021, 1, 57–64. https://dx.doi.org/10.3390/encyclopedia1010008 https://www.mdpi.com/journal/encyclopedia Encyclopedia 2021, 1, FOR PEER REVIEW 2 Encyclopedia 2021, 1 58 Attribution (CC BY) license Centesimal [dilution]”, thus referring to the method for preparation of homeopathic (http://creativecommons.org/licenses remedies invented by the German doctor [6]. Common formulations of homeopathic /by/4.0/). products found in the market usually include sucrose- and/or lactose-containing granules, and/orglobules lactose-containing (smaller than granules), granules, globulesand liquid (smaller drops than for granules), oral consumption; and liquid dropsother forformulations oral consumption; for local applications other formulations like creams, for local ointments, applications eye-drops, like and creams, nasal ointments, sprays are eye-drops,also available and (Figure nasal sprays 1) [7]. are also available (Figure1)[7]. FigureFigure 1.1. AA homeopathichomeopathic remedy. Homeopathic remedies are often produced produced in in the the form form of of gran- ulesgranules or globules or globules to be to taken be taken orally. orally. From: From https://pixabay.com/cs/photos/globuli-homeopatie-: https://pixabay.com/cs/photos/globuli-homeopatie- naturopatii-3163134/. naturopatii-3163134/. Originally,Originally, homeopathyhomeopathy waswas proposedproposed forfor thethe treatmenttreatment ofof anyany disease,disease, andand quicklyquickly gainedgained popularity,popularity, withwith oneone ofof thethe firstfirst institutions institutions dedicateddedicated toto itit beingbeing foundedfounded inin thethe USAUSA asas early early as as in in the the last last part part of the of nineteenththe nineteenth century century (the American (the American Institute Institute of Home- of opathy)Homeopathy) [4]. Since [4]. then, Since various then, various homeopathic homeop clinicsathic and clinics hospitals, and hospitals, even with even inpatient with services,inpatient have services, been have created been all created around all the arou world:nd the However, world: However, in Western in countriesWestern countries like the UK,like thethe publicUK, the financial public financial support support of these of facilities these facilities has mostly has beenmostly withdrawn been withdrawn in recent in yearsrecent and years the acceptabilityand the acceptability of this alternative of this alternative medicinal medicinal system in public-fundedsystem in public-funded healthcare systemshealthcare has systems been questioned has been openlyquestioned [4,8]. openly Similarly, [4,8]. in Similarly, France, it wasin France, decided it thatwas thedecided cost ofthat homeopathic the cost of homeopathic remedies is not remedies to be covered is not to by be the covered national by fund the fornational health fund as of for 2021 health [9]. Allas theof 2021 same, [9]. there All arethe European same, there countries, are Euro suchpean as Luxembourg,countries, such where as Luxembourg, homeopathic where reme- dieshomeopathic are still reimbursed remedies byare publicstill reimbursed health insurances by public [9]. Inhealth Italy, insurances although homeopathic [9]. In Italy, remediesalthough arehomeopathic to be paid forremedies by individual are to be patients paid for in anby “out-of-pocket”individual patients fashion, in an there “out-of- are apocket” few outpatient fashion, clinics there whereare a thefew cost outpatient of homeopathic clinics consultationswhere the cost is partiallyof homeopathic or fully subsidizedconsultations by theis partially public healthcare or fully subsidized system, depending by the public on personal healthcare income system, [10 ].depending The case ofon Switzerland, personal income in which [10]. homeopathy, The case of after Swit beingzerland, withdrawn in which from homeopathy, the list of reimbursed after being medicineswithdrawn in from 2005, the was list reintroduced of reimbursed as a medici basic healthnes in insurance-subsidized 2005, was reintroduced practice as a withbasic ahealth general insurance-subsidized referendum in 2009, practice shows that, with beyond a general the scientificreferendum debate, in 2009, popular shows support that, playsbeyond an importantthe scientific role debate, in regulating popular homeopathic support plays practice an important [11]. In general, role in worldwide, regulating specifichomeopathic regulations practice of homeopathy [11]. In general, largely worl varydwide, on the specific basis of regulations national laws, of ashomeopathy described inlargely a detailed vary reporton the issuedbasis of by national the World laws, Health as described Organization in a detailed in 2001 [report12]. issued by the WorldThe Health debate Organization around homeopathy in 2001 [12]. has a long history and almost dates back to its origin.The After debate years around of speculations, homeopathy discussion, has a long research, history and evenalmost fights dates and back controversies, to its origin. inAfter 2005, years a famous of speculations, editorial published discussion, in “The resear Lancet”ch, and concluded even fights that, an ind considerationcontroversies, ofin available2005, a famous scientific editorial evidence, published the history in of“The homeopathy Lancet” concluded had eventually that, comein consideration to an end [13 of], andavailable briefly scientific