Placebos: a brief review for family physicians

Abstract

Placebos are as old as the practice of medicine and for thousands of years represented nearly the totality of medical therapeutics. Positive and negative placebo effects occur in about 35 percent and 10 percent of individuals, respectively. Without exception, all medical therapeutics may be assumed to have significant placebo components. Factors contributing to the success of placebos are many, but include the expectations of physician and patient, the doctor-patient relationship, and societal norms. Ethical issues regarding the use of placebos are not clear-cut but, in general, the use of placebos is contraindicated except as an adjunct to specific therapy, or as a research tool with informed consent.