Placebo: a brief updated review

Abstract

Our aims were to provide updated information on placebo/nocebo effect and the potential use of placebo in clinical practice. This article can only provide a rough overview on the placebo and nocebo effect and is intended to serve as a starting point for the reader to go deeper into the corresponding literature. The placebo effect has been observed in multiple medical conditions, after oral administration, with manual therapies as well as with surgery and invasive procedures. The use of placebo in clinical trials is fundamental, although the ethics of its use is under discussion. The placebo may behave like a drug from the pharmacokinetic and pharmacodynamic point of view and can also be associated with adverse events (nocebo effect). Placebo can modify treatment by increasing or decreasing the effects of drugs. The factors associated with the occurrence of placebo effect are multiple, but in addition to those that depend on the placebo itself, the doctor-patient relationship would be the most important. As a result of findings that were published in the last two decades, the psycho-neurobiological basis of placebo is becoming better understood, although further studies are needed. In conclusion, the placebo effect in the clinic exhibits weak to moderate intensity. Placebo, in addition to its use in the clinical trial, should be considered another therapeutic remedy either as stand alone or in association with treatment, and could be useful in certain circumstances. The use of placebo should be regulated by the European health authorities through a guide in clinical practice that will improve patient care.

Placebo and nocebo effects and mechanisms associated with pharmacological interventions: an umbrella review

“…The retrieved psychobiological mechanisms of placebo/nocebo effects and placebo-related/nocebo-related effects associated with pharmacological interventions, together with their effect sizes, are reported in online supplemental appendix 6 . In summary, meaningful results have been found for the following clinical conditions: pain, 2 4 6 8 20 29–40 62 66–75 non-noxious somatic sensation, 76 Parkinson’s disease (PD), 2 6 41 77–79 migraine, 42–44 sleep, 45 80 intellectual disability (ID), 46 depression, 2 6 20 47 48 62 69 74 81–83 anxiety, 2 6 8 74 dementia, 2 4 49 84 addiction, 2 4 50 51 63 79 85 86 gynaecological disorders, 87 88 ADHD, 20 89 immune and endocrine systems, 2 4 20 79 90–92 cardiovascular system, 2 52 79 93 94 respiratory system, 2 79 95–97 gastrointestinal disorders, 6 20 53 62 74 98–100 skin diseases, 26 54 62 87 96 101–103 influenza and related vaccines, 55 104 oncology 20 26 53 62 96 and obesity. 9 105 106 Beyond the healing context, meaningful results have also been found for physical 2 56–59 107–109 and cognitive performance.…”

“…Significant responses to OLPs administration were documented for: pain (low back pain and ischaemic arm pain), 20 62 72 depression, 20 62 menopausal hot flushes, 87 ADHD, 20 89 allergic rhinitis, 20 IBS, 20 62 psoriasis 62 and cancer-related fatigue. 20 62 Also, the Hawthorne effect was documented in both dementia 84 and obesity.…”

Drug advertising in the German free-of-charge health magazine Apotheken Umschau (Pharmacy review): a critical analysis

“…We also analyzed to which extent the name of the preparation is suggestive and alludes to complaints that are to be alleviated. This could increase confidence in the effectiveness of the preparation and augment a placebo effect (Pardo-Cabello et al 2022 ). In 87% of the advertisements, the preparation name provided suggestive clues to the complaints or diseases that the preparation was intended to alleviate.…”

“…Future systematic clinical studies will have to examine to which extent different colours affect drug efficacy, via a placebo or nocebo effect. This constitutes a largely unchartered research area (Pardo-Cabello et al 2022 ).…”

“…Huh and Im ( 2021 ) reported that patients’ compliance about drug intake depends to a large extent on the advertised positive effects or the adverse effects presented. This most likely represents a placebo effect (Pardo-Cabello et al 2022 ). Thus, a placebo effect may convey the impression to the public (and federal authorities) that the advertised preparations “work”.…”