Physiotherapy December 2002/vol 88/no 12 735 Overview ‘Placebo’ is the Latin for ‘I shall please’ (Harrington, 1997). Shapiro (1961) defined the placebo effect broadly as ‘any therapeutic procedure (or that com- ponent of any therapeutic procedure) which is given deliberately to have an effect, or unknowingly has an effect on a patient, symptom, syndrome or disease, but which is objectively without specific activity for the condition being treated’. Placebo could be a subjective proced- ure that is administered by suggestion (French, 1994). Gaupp and associates (1994) classified the substances given as placebos as pharmacologically inert, pseudo-medicaments that are ordinarily prescribed for a different condition, or given in a sub-therapeutic dose. Although a placebo is usually implied to have positive effects, negative effects may also occur. Kissel and Barrucand (1974) coined the term ‘nocebo’ and referred to it as an inactive treatment procedure that may cause noxious effect. The focus of this paper, however, is on beneficial effects. Placebos have played an integral role in the practice of medicine for centuries. Approximately 4,785 drugs and 16,842 prescriptions were documented in ancient ‘medical’ records including those of the Yellow Emperor Huang Ti, Sumerian- Babylonian-Assyrian, the Ebers Papyrus, and the Hippocratic Corpus. It is startling, however, to find that the majority of these drugs were placebos (Shapiro and Shapiro, 1997). For example, in ancient Egypt, patients were treated with lizard blood, crocodile dung, the teeth of an ass, putrid meat, and fly specks, which were found to have no specific medicinal value (Gaupp et al, 1994). The first placebo-controlled clinical trial took place in 1916 (Gaupp et al, 1994). Gradually, researchers became more keenly aware of the importance of placebo-controlled clinical trials and the practice of using placebo control groups in clinical research began to emerge in the 1940s. However, it was not until 1945 that the word ‘placebo’ appeared in the title of medical articles (Gaupp et al , 1994). ‘Placebo analgesia’ refers to imp- rovements in a therapeutic context that are not due to specific therapeutic factors, but may be related to a patient’s intrinsic Placebo Analgesia Clinical considerations Summary Pain is the predominant symptom that prompts patients to seek medical advice and treatment from physiotherapists. Various treatment modalities such as heat and cold, electrical stimulation (Cheing and Hui-Chan, 1999), ultrasound, manipulative techniques, massage and laser treatment have been demonstrated in varying degrees to be clinically effective for managing pain of different pathologies. However, all these treatments could be assumed to have some placebo elements (French, 1994). From a research design perspective, the presence of placebo response is undesirable and must be controlled as it complicates the demonstration of ‘real’ treatment effect. From a clinical perspective, it is intriguing to note that the condition of patients in the placebo control groups did improve considerably in many of these validation studies, although in the majority the improvement was not so marked as in the treatment groups. Conspicuously, some neuro-physiological and psychological aspects of the placebo effects may have clinical use in enhancing the effect of pain treatments and their outcomes. Unfortunately, although placebo response has been a subject of continuing interest among some physiotherapy researchers and clinicians, information about placebo analgesia and its clinical utility is seldom discussed. The purpose of this paper is to provide clinicians with an overview of the construct and research related to placebo analgesia as well as a discussion of the potential clinical use of certain components of placebo analgesia to enhance pain rehabilitation outcomes in physiotherapy practice. Key Words Placebo, analgesia, pain. by Gladys L Y Cheing Kenny S H Cheung Cheing, G L Y and Cheung, K S H (2002). ‘Placebo analgesia: Clinical considerations’, Physiotherapy, 88, 12, 735-743.