Skeptics Have Two Bob Each Way

Even the skeptics (American English for ‘sceptics’) can’t come down *too* hard on placebos:

"A person’s beliefs and hopes about a treatment, combined with their suggestibility, may have a significant biochemical effect. Sensory experience and thoughts can affect neurochemistry. The body’s neurochemical system affects and is affected by other biochemical systems, including the hormonal and immune systems. Thus, it is consistent with current knowledge that a person’s hopeful attitude and beliefs may be very important to their physical well-being and recovery from injury or illness.
However, it may be that much of the placebo effect is not a matter of mind over molecules, but of mind over behavior. A part of the behavior of a "sick" person is learned. So is part of the behavior of a person in pain. In short, there is a certain amount of role-playing by ill or hurt people. Role-playing is not the same as faking or malingering. The behavior of sick or injured persons is socially and culturally based to some extent. The placebo effect may be a measurement of changed behavior affected by a belief in the treatment. The changed behavior includes a change in attitude, in what one says about how one feels, and how one acts. It may also affect one’s body chemistry.

From The Skeptics Dictionary