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There are several problems with double-blind testing that have become apparent in the last few years, and that call for a new standard testing procedure. Doubl
by Phemist 11y ago
There are several problems with double-blind testing that have become apparent in the last few years, and that call for a new standard testing procedure.
Double-blind rests, among others, on the assumption that a) placebo effects are independent of and additive with actual drug-effects, b) placebo effects are nulled when participants know they're being given a placebo.
Although I'm currently without sources (hopefully I can rectify this soon) both a and b are actually false.
Certain drugs have been found to interact with placebo, which decreases or enhances their effects, thus again conflating the medicative effects of the drugs being administered and the effects of actually taking a pill (or rather going through the process of administering medication).
Second, placebo has become such a household term, that the original meaning as a "fake" effect, seems to have been lost. Logically this makes sense, because its the end result that matters (being cured), not the way in which the drug is effective (placebo or not). The average person being told they're receiving a placebo can actually increase the placebo effect, rather than nulling it.
A second variable should be introduced in double-blind studies, to account for both factors I mentioned above. Variable 1 should be whether or not they're receiving the actual drug (1a) or a placebo drug (1b) (as double-blind currently tests for) and variable 2 should be whether participants are told that they're receiving the actual drug (2a), or a placebo drug (2b).
Testing the effects of combination 1a/2b vs 1b/2a should test whether the drug actually interacts with a placebo effect. Providing a measure of validity for the 1a/2a vs 1b/2a test.
EDIT: Fixed some spelling mistakes
EDIT2:
Found some sources: Guardian article on how placebo can be enhanced when participants know they're being given a placebo: http://www.theguardian.com/science/2010/dec/22/placebo-effect-patients-sham-drug http://www.theguardian.com/science/2010/dec/22/placebo-effec...
Published paper that used the set-up I suggested to find caffeine-placebo interaction effects - http://www.ncbi.nlm.nih.gov/pubmed/21092089 http://www.ncbi.nlm.nih.gov/pubmed/21092089
EDIT3:
This is the paper I remember reading on the subject - http://www.ncbi.nlm.nih.gov/pubmed/24416197 http://www.ncbi.nlm.nih.gov/pubmed/24416197
- Phemist 11y agoThis is, ofcourse, all based on whether a proper inert replacement for the drug-to-be-tested has been found.
- heliumcraft 11y ago"Certain drugs have been found to interact with placebo" ??
- kragen 11y agoActive placebos are chosen to have side effects similar to the drug being tested.
- Phemist 11y agoThis was sloppy on my part. I meant "interact" in a statistical sense - https://en.wikipedia.org/wiki/Interaction_(statistics) https://en.wikipedia.org/wiki/Interaction_(statistics). I'm not a medical expert, so I'm a bit inconsistent in terminology, but have ran my fair share of (cognitive) psychological experiments (and developed methods for them), which rely on similar logic as to that of double-blind testing.
- techdragon 11y agoGenuinely curious why you choose not to use "not given any drug" option in your combinations. Would this "baseline" not be useful in any capacity?
- Phemist 11y agoIt's a problem of testing the efficacy of going through treatment (with any substance, inert or active) vs testing the efficacy of a certain active drug. In double-blind experiments, where placebo effects are attempted to be disentangled from actual drug effects, such a baseline would introduce too many variables to be taken in account. There are psychological factors related to the participants response ("Hey, I joined this clinical trial, but I'm not being given anything, what's up with that?") that make it difficult to conclude anything from the results. The participant might even be adversely afflicted by this seeming "lack of care" from the experimenters side. Next to that, experiments might experience observer-expectancy effects, where the expectations of experimenters cause the participants to behave in certain ways. Also, if a positive result was found in the "not given any drug" vs "given the active drug" trial, one would still not be sure if this was due to the participant going through the treatment, or due to the treatment + the effects of the drug.
- austinjp 11y agoSee my comment elsewhere in this thread. This does indeed happen in some trial designs.