For he first time, a physiological mechanism for the 'placebo effect' has been discovered by scientists.
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SYDNEY: A key to understanding the mysterious 'placebo effect' has been unlocked by scientists: placebos may work by blocking pain signals in the spinal cord from reaching the brain.
The placebo effect has long been a scientific mystery: it occurs when a patient's medical condition responds to treatment that is either fake or contains inactive substances. It was originally thought to be a psychological phenomenon related to the perception and expectation a patient has; if the inactive substance (or 'placebo') is viewed as helpful, it may heal, but if it is viewed as harmful, it can cause negative effects.
"We found that when people experience pain relief due to a placebo administration, they also show reduced neuronal activation to painful stimulation in their spinal cord," said research team member Falk Eippert, a neuroscientist with the University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
"This shows that psychological factors such as placebo can have a profound impact on pain processing."
Conditioning and expectation
Currently, the placebo effect is thought to depend mainly on two phenomena - conditioning and expectation. Conditioning is a process when, for example, we see a doctor several times who helps us to recover each occasion. Eventually we are conditioned to get better simply by going to the doctor - no longer is therapy required to make us recover.
Expectation is a more conscious process that depends on the context of a therapeutic situation. For example, if we are made to expect that a certain treatment will improve our health, we then might get better even if the actual treatment does nothing at all.
Both mechanisms work together and help to generate therapeutic benefits.
Placebos are typically used as 'controls' in experiments that test new treatments: patients are randomly given either the real drug or a placebo, and neither they nor the staff administering the trial know which patient has received the real treatment. Often, some of the patients given inactive substances also improve.
When a substantial number of people taking the placebo get better too, it makes it hard for researchers to determine whether a new drug is actually of any benefit. Placebos can be applied to a variety of illnesses, and when they have a pain-relieving effect (as in this study), this is called 'placebo analgesia'.
Deep in the brain
While there has long been an understanding that the 'placebo effect' is rooted deep in the brain, recent advances in imaging technology allowed the scientists to scan neuronal activity in the spinal cord. This part of the body acts as the entry station of the central nervous system for pain messages that come from the body.
This showed that psychological factors, such as placebo, can have a profound impact on pain processing, affecting not only cognitive areas deep in the brain, but down the spinal cord, where neuronal activity was inhibited.
Expectations
It seems to me that the flaw in the study is that the subjects are /expecting/ pain when the painful stimulus is applied. Maybe being told that a useless cream has been applied will make it more painful than no cream at all? A kind of negative placebo, which has focused the subject's mind on the pain. IMHO there should be 3 sets of measurement: Nothing, cream declared useless and cream declared effective.
Nothing to See Here
I'm confused by the notion that we've never considered a physical effect on the brain. While it's safe to say that there's uncertainty in how our brain is physically effected by our beliefs and emotions, don't we still draw this conclusion? That's the whole basis behind treating assumed chemical imbalances, isn't it?
Mechanism for placebo
"The scientists suggest this may be because when patients expect a treatment to be effective, the brain area responsible for pain control is activated..."
How does the body know what the mind is thinking?