January 31, 2006
Redefining Placebo and Pain
Humans—and rightfully so—are obsessed with reverse engineering our brains. Neuro-cartographers are busily mapping brain function via functional magnetic resonance to advance our obsession.
According to Wikipedia, “a placebo , from the Latin for "I will please", is a medical treatment (operation, therapy, chemical solution, pill, etc.), which is administered as if it were a therapy, but which has no therapeutic value other than the placebo effect."
Other expressions of placebo include things like “a useless treatment”. One with no effect. Pharmacologically inert. The proverbial “sugar pill”.
And then again, maybe not.
Functional magnetic resonance imaging (fMRI) is a technique whereby one can “see” which parts of the brain receive blood flow during different thought processes or stimulations implying brain activity in response to the activity. Place a person in a fMRI machine and ask them to think of being at their favorite place and watch the “pleasure centers” light up. And so forth.
Significant insights into the physiologic nature of placebo effect started to coming to light three or so years ago by this technique and have been carried a step further recently.
As a practicing physician, the placebo effect was either one of your best friends or nettlesome noise in the system. I seem to recall something on the order of two-thirds to three-fourths of people had the same effect with placebo as with pharmacologically active therapy for pain. Hence, any new treatment being studied had to surpass this threshold to be deemed effective.
The question: is it real? Of course, that begs the question, “What is real?”
In published reports in Science starting around 2002, fMRI began to show that in response to pain the same neurological pathways were activated by both placebo and pharmacologic therapy. That was a real “wow!” Placebo and medication work the same way at least at the central nervous system level.
So, does that make them both placebos or both therapeutic?
New studies continue to expand the placebo-neural-pathway connection and the activation of the opioid portions of the brain. The Associated Press reported on November 29 on studies from Columbia University and University of Michigan .
“Your medicine really could work better if your doctor talks it up before handing over the prescription.”
“Research is showing the power of expectations, that they have physical -- not just psychological -- effects on your health. Scientists can measure the resulting changes in the brain, from the release of natural painkilling chemicals to alterations in how neurons fire.”
“Among the most provocative findings: New research suggests that once Alzheimer's disease robs someone of the ability to expect that a proven painkiller will help them, it doesn't work nearly as well.”
"Your expectations can have profound impacts on your brain and your health," said Columbia University neuroscientist Tor Wager.”
"There is not a single placebo effect, but many placebo effects" that differ by illness, said Dr. Fabrizio Benedetti of Italy 's University of Torino Medical School, who is studying those effects in patients with Alzheimer's, Parkinson's disease and pain.”
So, the earlier basic science work is now being investigated in specific instances of disease, with much the same finding.
Perhaps more interesting were the findings from a recent Stanford study showing that individuals could be trained to suppress pain using feedback and monitored in fMRI machines.
As reported in Science News Online December 17, “Preliminary evidence indicates that people can quell either temporary or chronic physical pain by learning to use their minds to reduce activity in a key brain area.”
“Brain-imaging technology now enables individuals to use mental exercises to control a neural region that contributes to pain perception, say neuroscientist Sean C. Mackey of Stanford University and his colleagues.”
“Both healthy volunteers and chronic-pain patients "learned to control their brains and, through that, their pain," Mackey holds. "However, significantly more testing must be done before this can be considered a treatment for chronic pain."
As a diabetic patient once explained to me as I was instructing him on the diabetic exchange diet: “Eggs is not meat!”
Patients often show us universal truths. In this case placebo is not pharmacological. But the real question is how do we take this natural ability and use it with or without pharmacologically active substances to enhance our lives?
And what is real? This is really getting interesting.
Robert B. Teague is a pulmonologist and business consultant who is based in Houston, Texas. E-mail him.
Read other blogs in this series.
