Thought Broadcast

It has long been known in medicine that placebos can be surprisingly
effective, for the treatment of a wide range of disorders.  A placebo, whose name is taken from
the Latin for “I please,” is an inert substance, a sugar pill, that
should have little to no effect on any physiological process.

A “placebo-controlled study” is considered the gold standard in medication
trials; in such a study, half of the patients with a given condition
are prescribed an active medication, while the other half are
prescribed a placebo.  In virtually all studies, there is some
improvement in the placebo group, and this improvement can, at times,
be significant.  In trials of antidepressants, for example, it has
been estimated that up to 75% of the antidepressant response may be due
to a placebo effect, an observation that has received much
popular press of late.

A research group at Harvard Medical School has taken this one step
further.  They took a group of patients with irritable bowel
syndrome (IBS), gave half of them a placebo, and the other half nothing.  (This would be, I
guess, “placebo-placebo controlled study”!)  More importantly,
however, they even told the
placebo group that they were getting a placebo!  Specifically,
they told patients that they would get “placebo pills made of an inert
substance, like sugar pills, that have been shown … to produce
significant improvement in IBS-symptoms.”

In their report (available freely here), they
showed that the placebo was more effective at treating IBS symptoms
than nothing at all, and– even though they did not directly compare
placebo to any active medication– they found that the rate of
improvement was twice the success rate of the most powerful IBS
medications.

While this raises several important questions about the utility of
placebos in medicine, it also hits at the heart of a lot of what we do
in psychiatry.  Most psychiatrists have the experience of seeing a
patient fail multiple medications but exhibit a positive response to
yet another medication from the same class, for no obvious
reason.  Or giving two similar patients the same medication and
finding that one responds while the other does not.

Modern biological psychiatry looks at situations like these and asks,
what are the interindividual biochemical or physiological differences
that predict response to one agent over another?  Are there
genetic or other biological markers that make one person a better
candidate for medication X than for medication Y?

This study, however, raises new questions in situations such as
these.  If patients’ symptoms can improve after taking an inert
substance (and I’d be interested to see a repeat study on patients with
a mental illness– although IBS itself is a “psychosomatic” illness
with strong psychological features), this result cannot be ignored and
ascribed to chance.  Something is
working in this treament, but exactly what?  Is it the way we talk to patients about
treatment?  Something about patients’ expectations of treatment?  If
patients don’t believe that their meds will work, does this prompt them
to enact more effective behavioral changes in their lives?  It
appears that patients have more of an ability to solve their problems
than we often give them credit for, and this study should prompt us to
look for those strengths, not serve as ammunition to attack the
weaknesses of psychiatric medicine.

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