Medescape

Skepticism, Medicine and Science News

The Placebo Gene

Most people are familiar with the placebo effect, and in general terms it is the therapeutic effect of an inert/ineffective treatment. People tend to get better just because they believe they will, and placebos are therefore used in double-blind trials as a way of eliminating the placebo effect from the final results. 

It is not really surprising that the effect is as substantial as it has been shown to be. Of course, a placebo will do you no good when treating a bacterial infection for example, but for non-specific, general symptoms such as pain, they tend to do very well. The perception of pain is highly regulated in the brain, and I’m sure everybody has experienced that the amount of pain felt varies greatly according to whether you know something painful is about to happen or not. 

Even though the placebo effect is well known and widely used in clinical medicine and research, it is not thoroughly understood. In a recent article though, scientists have managed to link a specific gene to increased susceptibility to the placebo effect. The research was done by researchers at Uppsala University in Sweden, and published in the Journal of Neuroscience. The study looked at 25 patients with social anxiety disorder, and over an 8-week period they recieved a placebo that they were told would help improve their condtition (of course, neither the patients nor the doctors knew the drug was a placebo). At the end of the period, a positron emission tomography (PET) scan was done and compared with one done 8 weeks prior. 10 of the patients responded to the placebo treatment, and 8 of these varied genetically from the others. The researchers found that these 8 had two copies of a particular G-variant of the gene that codes for tryptophan hydroxylase-2, an enzyme involved in the process of synthesizing the neurotransmitter serotonin. None of the other participants had two G-copies of the gene, and Tomas Furmark, lead scientist, believe the effect of this gene may extend to other phenomena associated with the amygdala, such as depression and pain disorders. 

The sample size of the study was not, however, very impressive, and the results would have to be externally replicated before any real conclusions could be made. Also, the general consensus is that there is no single placebo effect, but a lot of different mechanisms that together make up the whole, including genetic factors. Still, a nice advance in placebo research. Full paper can be found here.

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December 3, 2008 Posted by | Medicine, Neuroscience, Psychology | , , , , , , , , , , , , , , , , , , , , , , , , , , , | Leave a comment

Body Swapping

Scientists at the Karolinska Institute in Stockholm have managed to create the illusion of “body swapping” in the lab. They were able to fool volunteers into perceiving the bodies of both mannequins and other people as their own by using CCTV cameras and physical stimulation. Pretty cool….

December 2, 2008 Posted by | Neuroscience, Psychology | , , , , , , , , , , , | Leave a comment