Posted by SLS on July 30, 2005, at 10:19:03
In reply to We need placebo, posted by med_empowered on July 29, 2005, at 16:23:58
Hi.
> Here's the thing: if the argument is that depression is a medical condition that is best treated medically, we *need* a placebo control-
Not unless the placebo effect is real and/or part of the natural course of the illness in those "responding" individuals. A 30-35% response rate to placebo makes clinical trials almost meaningless. I have often thought that the high rate of placebo response was the result of poor inclusion/exclusion criteria. When one includes only a population of depressives rated as severe, the placebo response approaches zero while the response rate remains at 65-70%.
Just a spur of the moment idea: It might make sense to use a placebo-placebo control in addition to the active group, and extend studies for 4 months rather than 6 weeks. A high percentage of placebo responders tend to respond very early in a trial and relapse after 10 weeks. I would separate out anyone whom has continued to be a placebo responder by 10 weeks. I would then crossover the placebo non-responders to active compound and continue them for another 6 weeks. It would be preferable to use an active placebo, or those crossing over will be again subject to a placebo effect when the investigational compound is introduced and its side effects recognized. Now one may more easily compare the rate of response to non-response.
The desirability of using placebos in trials of antidepressants is more complex than this. Since there is much more to this issue than I am capable of presenting right now, I might suggest you start researching the matter using an Internet search engine using keyword phrases like:
- placebo Quitkin
- placebo antidepressants meaningless> -this is, afterall, how we evaluate all other medical treatments (including other psychotropics, such as neuroleptics or anxiolytics).
I am not knowledgable enough to be able to speak to all other medical interventions. Certainly, ethical considerations must prevent the use of a placebo in some circumstances.
> The FDA recognizes the importance of the placebo effect--
Some people tend to propel the FDA to a status of infallability at times and bash the FDA at others. I would like to leave the FDA out of this debate and include only the research and medical commentary itself.
> Then again...many depressive episodes are self-limiting, so if one left a patient alone for 6-12 months the odds of that individual recovering from depression w/o any sort of intervention are pretty good, too.
One might consider withdrawal of the active compound for two weeks after a response, and then rechallenge if a relapse ensues. Stuff like this has been done before.
> Instead of questioning placebo--which is a necessary control for medical research--
I am not convinced that placebo controls are necessary for medical research. Like I said, there is much debate surrounding this issue.
These drugs. Perhaps our studies of these drugs do not.
- Scott
poster:SLS
thread:534296
URL: http://www.dr-bob.org/babble/20050728/msgs/535591.html