How Does the Placebo Effect Work?

Typically, as people experiencing dis-ease, we want to know whether a therapy works. We are less concerned to know how it works, just whether it works.Just how the placebo effect comes about is unresolved, despite the burgeoning research effort. Theories include:

• Benefit from attention – we respond positively because we receive enhanced and focused attention from a practitioner

• Stimulus response – like Pavlov’s dogs, we respond somatically to the suggestion which accompanies the administration of a therapy because we have experienced benefit from such therapy in the past

• Beliefs, expectations, and the attribution of meaning – as with stimulus-response, our assumptions and expectations about the efficacy of a therapy conditions a somatic response: the higher our expectations, the greater our response

• Relationship with therapist – we respond positively to positive relations with our therapist

• Pleasing the therapist – in our effort to be ‘good patients’, we respond positively to our therapist’s expectations (1)

It is reasonable to say that there is no scientific consensus on how it works. In general, most agree that the placebo effect (and its reverse, the nocebo effect, where negative reactions are experienced) operates in the borderland between the ‘mind’ and ‘body’ constructions assumed by conventional medicine. And while conventional medical science has little to offer us by way of explanation, our subjective experience of the placebo effect needn’t baffle us.

Michael Jospe, a professor at the California School of Professional Psychology who has studied the placebo effect for more than 20 years, points out that all people experience physiological reactions to anticipation and stress--something like the fight-or-flight response--that help them to survive and cope. When you step out of your office and a spider jumps out at you, Jospe analogizes, "you'll get a fright and have a physiological reaction. And the next time you go out that way, the thought that it could happen again can produce a physiological reaction before you even open the door." So, he says, the relationship between a thought and a negative psychophysiological reaction like fear is something we experience daily.

That goes for positive associations, too, Jospe continues. "The placebo effect is part of the human potential to react positively to a healer. You can reduce a patient's distress by doing something which might not be medically effective." It's like kids and Band-Aids, Jospe says. "When you put a Band-Aid on a child and it has stars or comics on it, it can actually make the kid feel better by its soothing effect, though there's no medical reason it should make the child feel better." (2)

Refs(1) Mayo Clinic - Consumer Health Tips and Products, Placebo Effect: Harnessing Your Mind’s Power to Heal, December 30, 2003, (2) Tamar Nordenberg, The Healing Power of Placebos, US Food and Drug Administration