There is a Nocebo Effect which is the Evil Twin of the
Placebo Effect
Today I found out about the “nocebo effect” which is more
or less the evil twin of the placebo effect.
The nocebo effect is an effect where a patient is given or told
something that should make no difference whatsoever to their health, but ends
up causing negative side effects because of what they believe about the thing
they are taking or is done to them.
Similar to the “placebo” effect where patients are given a similar such
agent that ends up positively affecting their health.
The name ‘nocebo’ was chosen by Walter Kennedy in 1961 to
describe these results caused by negative suggestion as it is specifically
Latin for “I will harm”, whereas ‘Placebo’ is Latin for “I will please”. So if given some fake medication that should
do nothing and it produces a positive result, it is to be called a placebo
result; if negative side effects are reported than a nocebo result; both being
caused only by the patient’s expectations and not from any other outside
factor.
Despite Kennedy suggesting this all the way back in the
1960s, it wasn’t until the 1990s that distinguishing between a placebo and a
nocebo became popular. Prior to that,
they were just all called placebo effects or placebos. Indeed, even today it is somewhat
controversial to have a separate name for these two things as it is entirely
possible to have a fake drug given that could be accurately described as both a
placebo and a nocebo. Such as the case
where a person is given a sugar pill and told this “drug” will take away their
headache, but may cause dry skin. If the
patient reports that it takes away their headache, but they now have dry skin,
then it is both a placebo and a nocebo, which can obviously be confusing. Though the benefit to this terminology is
that the specific effects can now be more accurately distinguished; referring
to the placebo effect for the positive result of taking away the headache and
the nocebo effect being the negative result of dry skin; both as a result of
this fake agent combined with the patient’s belief about what they are taking.
Because of the potentially negative side effects caused
by the patients own beliefs, which can even be lethal at times, research on
nocebos has been very scarce, though there are some well documented cases such
as a study where 34 college students were hooked up to a machine and told that
a small amount of electric current would be passing through their heads and it
should cause them to have a headache. In
fact, the machine did nothing, but over 2/3 of the students reported developing
a headache while hooked up to the machine.
Another interesting one that demonstrates both the
placebo and nocebo effect in one study is a study done by Japanese researches
on 57 high school aged boys. They
selected these boys based on the fact that when exposed to Lacquer trees, these
boys would get a severe rash, much like is common with poison ivy. They then blindfolded the boys and proceeded
to brush one of their arms with the Lacquer tree leaves and the other with an
innocuous leaf that would have no effect.
They told them however that the arm brushed with the laquer tree was
brushed by the harmless leaf and the one brushed by the harmless leaf they were
told was brushed by the Lacquer tree leaf.
What followed was a rash developed on most of the boys arms that were
brushed by the harmless leaf and the other arm that was actually brushed by the
Lacquer leaf that should have caused a rash was completely fine in nearly every
case.
Another such study where both the placebo and nocebo
effects were observed was an experiment with asthmatic patients. They first were made to breath in a vapor
that they were told was an irritant or allergen, but in fact was harmless. About 50% of the patients proceeded to
experience breathing problems, with several experiencing full blown asthma
attacks. All the patients who had
trouble were then treated with “medicine” and all recovered immediately. In fact, both the irritant and supposed
medicine were the exact same solution, nebulized saltwater.
This effect has also been observed very commonly in
patients who fixate on supposed side effects of real medication. Even when given a nocebo, many will report
having the negative side effects that can be associated with the real drug. Indeed, both the placebo and nocebo effects have
been observed recently to be becoming “more effective” in that placebos are
suddenly working better and likewise more people given fake drugs are reporting
the side effects associated with the actual medicine. It’s theorized, though nobody really knows
why, that this could well be because people are now much better informed about
the drugs they take and the side effects, both through more drug advertisements
and the readily available information on the internet.
In some cases, this nocebo effect has actually been
lethal to patients. For instance, in the
1970s doctors diagnosed a man with liver cancer and told him he had just a few
months to live. This was not some sick
trick, they really thought he had liver cancer.
He died within a few months of apparent liver cancer like effects. Upon doing his autopsy though, they found the
doctors had been mistaken and he did not in fact have liver cancer at all and
other than being dead, had a healthy enough body.
This effect is also why doctors will often not tell
patients when a procedure may be particularly painful. It has been found that in doing so they
drastically increase the amount of pain the patients report feeling throughout
the procedure. Likewise, doctor’s
warning about all possible side effects of a particular drug seems to
drastically increase the number of side effects patients experience, even when
given nocebos. By neglecting to be 100%
honest with the patients about negative side effects, it generally seems to
work out better for the patients because of this mysterious nocebo effect. Likewise, being overly optimistic about the
positive effects of some drug seems to drastically increase the effectiveness
of the drug because of the equally mysterious placebo effect.
Exactly why either of these things should be the case is
not yet understood.
[image source: photostock.com]
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