THE ROUGH GUIDE TO PSYCHOLOGY
The idea that mere beliefs can lead to physiological changes and
reduce disease symptoms seems almost magical. Expectation that the
treatment will be effective is crucial, and can influence how powerful
the effect is. For example, four sugar pills are more effective than two for
treating gastric ulcers; saltwater injections are more powerful than sugar
pills (presumably because the injection paraphernalia creates a more
powerful expectation of relief ); and pink sugar pills are more effective as
a stimulant than green ones.
Some instances of the placebo effect are truly astonishing. Consider
research by Cynthia McRae of the University of Denver, which compared
the effects of a radical new treatment
for Parkinson’s – implanting embryonic
dopamine neurons into the brain – against
a “sham surgery” control condition. The
sham surgery was just like the real thing,
except that the needles were empty and
didn’t pierce the brain. This meant that
there wasn’t any way for the patients to
know which group they were in. When the
patients were followed up several times over the following year, both
groups showed significant benefits. Remarkably, the strongest predictor
of quality-of-life improvements wasn’t the group a person was in, but
the group they thought they were in. That is, those patients who thought
they’d had the treatment – even if they hadn’t – tended to show the
greater improvements in their quality of life.
Unfortunately, the placebo effect has an evil twin known as the
nocebo effect. This is the phenomenon whereby the expectation that
something is harmful, even if it isn’t, can actually lead to negative
effects. Some experts believe the nocebo effect could explain why some
people report experiencing headaches after exposure to electrical
devices like mobile phones. Lab studies under controlled conditions
haven’t been able to recreate the symptoms that many people insist are
caused by mobiles. This suggests that it could be the mere belief that
phones are harmful which causes some people to experience negative
symptoms after using them.
“All bow before the
might of the placebo
effect, it is the coolest,
strangest thing in
medicine.”
Dr Ben Goldacre