Kaptchuk offers some ideas about what the key factors might be in the placebo effect (i.e. in positively enhancing healing, but not from the material effects of the treatment or drug). He suggests it is the effect of hope, attention and care; and to do with the social, not just their personal, beliefs i.e.(Pygmalion effect)
In turn that suggests these points:
• It has been established that persistent stress (unlike sharp, but passing, shocks) reduces immune system function. One service which doctors can perform is to tell a patient that they will recover. This is often not at all certain to the patient and their family. One of the reasons for mental illness being frightening to most people, is they don’t believe it will pass: this is in strong contrast to flu, food poisoning, broken bones, where they know they will recover. The assurance relieves anxiety and stress, which in turn improves immune system functioning, and so recovery.
• Thus it could be that inducing a patient (and those around them) to care for themselves is sometimes a key factor, and the basis for real healing effects independent of material interventions. This thought is further supported by the consideration that today in developed countries, the leading causes of death (heart disease, cancer) are thought to be largely controlled by lifestyles that the patient, not doctor, controls: persuading patients to behave differently is the key to controlling mortality.