A new study has asked whether
certain people with chronic pain should be given sugar pills to manage their
symptoms. Scientists tap into the individual differences that make some people
more susceptible to a placebo.
Brain anatomy and personality type
may influence susceptibility to the placebo effect.
A placebo is a medical
intervention — be it a pill, injection, or sham surgery — that has no
therapeutic value.
The placebo effect refers to the
real benefits that these inert interventions can have.
The simple act of taking a tablet
can make a person feel its benefits.
However, this is not just a
psychological phenomenon; it has a biological basis.
As one example, some studies have
shown that a placebo can affect blood
pressure; a clear physiological response.
However, the placebo effect is most
apparent in conditions that rely on self-reporting of
symptoms, such as anxiety, irritable bowel syndrome,
and chronic pain.
In chronic pain trials, for
instance, the placebo effect can often be as great as the response to the
treatment that is being tested. In actual fact, the response to a placebo can sometimes
be largerthan the response to conventional treatment.
Placebo as
a viable option
Because the standard drugs that are
used to treat chronic pain can have significant adverse effects over time, the
potential for an inert tablet to benefit some patients is of great interest.
One of the difficulties, though, is that not everyone is equally susceptible to
the placebo effect.
A recent study set out to probe this
problem: could it be possible to predict the size of someone's response to a
placebo before they take it? The results were recently published in the
journal Nature
Communications.
To investigate, scientists at
Northwestern University in Illinois studied 60 volunteers with chronic back pain. They split the
group into two study arms; one took either the drug or placebo, while another
attended the clinic but underwent no treatment.
Each person completed a number of
in-depth questionnaires that assessed their personality and the type of pain
that they experienced. They also went through four neuroimaging sessions.
As expected, some individuals who
took the placebo felt significant pain relief; these participants were then
examined further.
The scientists found that those who
responded to the placebo had asymmetry in their subcortical limbic system,
which is a part of the brain involved in emotion.
Particularly, the investigators
found it to be larger on the right side than on the left. These people also had
a larger cortical sensory area than those who did not respond to the placebo.
Also,
volunteers with a strong placebo response were more emotionally self-aware,
mindful of their environment, and sensitive to painful situations.
No need
for secrets
Study author A. Vania Apkarian, a
professor of physiology at
Northwestern University, believes that "[c]linicians who are treating
chronic pain patients should seriously consider that some will get as good a
response to a sugar pill as any other drug. They should use it and see the
outcome. This opens up a whole new field."
Giving a patient a placebo can seem
somewhat underhanded, but for those who are sensitive to its powers, this need
not be the case.
"You can tell them, 'I'm giving you a drug that has no
physiological effect but your brain will respond to it.' You don't need to hide
it. There is a biology behind the placebo response."
Prof.
A Vania Apkarian
These results could be significant
for people with chronic pain and other conditions, and they might also
revolutionize the way that some clinical trials are carried out.
The placebo effect has long been a
thorn in the side of medical research; knowing exactly what has relieved the
symptoms — be it the drug or the placebo effect — can never truly be known.
However, if researchers know which
participants are likely to have larger placebo responses, they can screen them
out initially, providing more reliable results in the long run.
As Prof.
Apkarian explains, "Drug trials would need to recruit fewer people, and
identifying the physiological effects would be much easier."
The more we understand about the
placebo effect, the closer we get to treating illnesses without the need for
toxic chemicals. "It's much better to give someone a nonactive drug rather
than an active drug and get the same result," Prof. Apkarian adds.
Although the placebo effect holds a
great many mysteries left to solve, the more we understand, the closer we get
to treating certain conditions in a much gentler manner.
No comments:
Post a Comment