Posted by ed_uk on July 31, 2005, at 6:56:17
In reply to Re: We need placebo » ed_uk, posted by SLS on July 30, 2005, at 20:50:13
Hi Scott,
>However, I think the way that we approach evaluating the efficacy of antidepressants must be viewed in the context of the high rate of placebo response.
I agree. The placebo response is very high and seems to be rising - I've had the impression that new studies seem to have higher placebo responses than older ones. I think you're right that it's related to the selection criteria..... and perhaps due to impressive nature of being in a study of a new drug.
>I would still want to look to do studies in which the inclusion criteria included only the more chronic and severe cases of depression.
I agree. Also, drugs with a novel mechanism of action ought to be tested on patients who are resistant to a few current therapies eg. at least one SSRI, one TCA and Effexor.
>What would happen if we included only those severe cases where cortisol levels were abnormal?
Probably a poor placebo response and a good response to something like nortriptyline.
>If 30% of those included in the study are primarily psychologically depressed rather than biologically, but still qualify under DMS IV criteria for major depressive disorder, how would we want to interpret a placebo response of 30%?
It's always difficult to do clinical trials of drugs for MDD due to the relatively heterogeneous group of patients included - despite the selection criteria (which exclude many patients who'd be treated with ADs in practice).
Also, people with definite biological abnormalities can respond to placebo eg. post-operative pain could be relieved by a saline injection (which was supposed to be morphine).
Kind regards
~Ed
poster:ed_uk
thread:534296
URL: http://www.dr-bob.org/babble/20050728/msgs/535918.html