The psychological factors that induce positive or negative responses to certain drugs, irrespective of their chemical properties are known as placebo effects. The word placebo is derived from Latin and means “I shall please”. Placebo is usually an inactive substance given to merely pacify the patient and they are used when there is no need for drugs for treatment and to help patients feel that they are well cared for. Placebos are most useful in the case of double blind experiments, in the context of scientific studies on the effectiveness of drugs.
For a traditional placebo, the main characteristic is a lack of side effects. But sometimes there may be some positive or negative effect due to placebos. Generally, the “placebo effect” refers to an apparent improvement in health due not to any treatment but only to the patient’s belief that he or she will improve. Scientifically speaking, the placebo has been defined by Arthur K. Shapiro, MD, in 1964 as “any therapeutic procedure which is given either deliberately to have an effect, or unknowingly and has an effect on a symptom, syndrome, disease, or patient but which is objectively without specific activity for the condition being treated” and the placebo effect as “the changes produced by placebos” (Shapiro, 1964, p. 136).
Placebo effects exhibit characteristics that are similar to those of active medication. Research shows that they show placebo effects are dependent on dosages, time, drugs given along with placebos and leave some withdrawal effects in some cases as well (Peters, 2001). Placebo effects can be either negative or positive and sometimes they can be addictive too (Peters, 2001). The proportion of patients who show positive placebo effects differs with different diseases and also with groups with the same disease.
For example, in depressive illness the rate of placebo effect varies from 25% to 60% and in schizophrenia, a related depressive disorder, it may vary from 20% to 50% depending upon the criteria used to measure improvement and other factors (Cookson et al, 2002). Generally, chronically ill patients do not respond favorably to placebos and have lower placebo effects. Another important characteristic of placebo effects regards the nature of placebo effects shown in the context of time. Studies show that the time course of improvement in depression differs in patients improving on placebo from those improving on active treatment.
The main difference is that when the placebo effects show up early, patients have a fluctuation course of improvement. But, they have been found to be more easily responsive to further treatment with placebos or drugs compared to those patients on active medications (Cookson et al, 2002). In many cases, the placebo effect may add on to the pharmacological effect when an active drug is used and can prove to be beneficial to the patient.
It has been found that placebo effects depend on a number of factors. According to Hanson et al (2005) the placebo effect is most likely to occur when the individual has a flexible mind set that is open to suggestions. In some persons or in particular settings, placebo effects are quite powerful. For example, placebos administered as pain killers have found to provide dramatic relief. The factors that affect the placebo effects are patient variables, physician variables and situational variables.
Patient variables include “attitude towards the physician, the treatment and the illness; levels of anxiety, expectation, education and past experience”; Physician variables include “credibility, enthusiasm, authority, empathy and sympathy”; situational variables include “location and form of treatment, interactions with staff and family, content and meaning of instructions and suggestions” (Shapiro, 1996, p. 71).
Although the placebo effect is not completely understood, one important psychological factor contributing to the placebo effect has been widely accepted in the expectation to improve in the mind of the patient. This expectation can be created by inducing the positive belief in patients that they can control the disease by taking a drug. For example in the case of stress, when the patient is prescribed tranquillizers, he believes that he can now control the symptoms of emotional stress to some degree and this belief ensures that a treatment will be effective and causes symptom reduction (Baum et al, 2001, 102).
Placebo effects are not generally used for treatment purposes but they must be understood in order to interpret the outcomes of both pharmacologic and non-pharmacologic therapies. In the industrialized world, the general public is largely biased to a biomedical model to explain symptoms and do not favor psychological explanations. Hence the idea of taking pills for psychological disorders is more appealing than the alternative path of self analysis and correction.
Baum, Andrew; Revenson, A. Tracey and Singer, E. Jerome (2001). Handbook of Health Psychology. Lawrence Erlbaum Associates, Mahwah, NJ.
Hanson, R. Glen; Venturelli, J. Peter and Fleckenstein, E. Annette (2005). Drugs and Society. Jones & Bartlett Publishers.
Peters, David (2001). Understanding the Placebo Effect in Complementary Medicine: Theory, Practice, and Research. Churchill Livingstone Publishers, Edinburgh.
Shapiro, A.K. (1964). Factors contributing to the placebo effect. American Journal of Psychotherapy, 73, suppl.: 73-88.
Shapiro, P. Alvin (1996). Hypertension and Stress: A Unified Concept. Lawrence Erlbaum Associates.