ABSTRACT
Armed with a credible theory and mechanism, the physician healer can be more confident, and consequently more effective, in his role. There are two main theories as to why placebos work and these have a direct bearing on the efficacy of the physician healer. Pavlov, the father of classical conditioning theory, was the first to report a conditioned placebo effect when he observed that dogs showed morphine effects, whenever they were placed in an experimental chamber where they had previously received morphine. GPs almost universally use placebos in some circumstances but tend to have negative feelings about doing so. Conditioning theory would dictate that the frequent use of placebos by a doctor would make them increasingly ineffective and that the most effective way of maintaining a placebo effect is to give mainly active drugs. The second theory, concerning expectation, is simply an offshoot of classical conditioning theory.
