Posted by SLS on May 12, 2010, at 6:03:45
In reply to Re: Interesting article? What do you think? » SLS, posted by 49er on May 10, 2010, at 9:32:32
> > Interestingly, the rate of response to placebo has increased rapidly over the years. This has reduced the apparent margin of statistical superiority of drugs. My guess is that this is an artifact of the use of less rigorous screening for major depressive disorder (MDD) and the inclusion of more people who don't suffer from it. (Clinical investigators are payed based on the number of subjects enrolled). One way or another, this trend must be accounted for if statistics are to be of any value. It is significant that when working with inpatients or people with more severe depressions, the placebo response rate plunges. Another guess of mine is that this occurs because a greater percentage of subjects actually have the illness being investigated.
> I will have to look up the statistics for inpatient folks and placebo rates. I haven't seen any studies on that. If you have link, that would be appreciated.
Here is the most recent study I could find:
http://www.ncbi.nlm.nih.gov/pubmed/20051569JAMA. 2010 Jan 6;303(1):47-53.
Antidepressant drug effects and depression severity: a patient-level meta-analysis.Fournier JC, DeRubeis RJ, Hollon SD, Dimidjian S, Amsterdam JD, Shelton RC, Fawcett J.
Department of Psychology, University of Pennsylvania, 3720 Walnut St, Philadelphia, PA 19104, USA. jcf@sas.upenn.edu
Abstract
CONTEXT: Antidepressant medications represent the best established treatment for major depressive disorder, but there is little evidence that they have a specific pharmacological effect relative to pill placebo for patients with less severe depression. OBJECTIVE: To estimate the relative benefit of medication vs placebo across a wide range of initial symptom severity in patients diagnosed with depression. DATA SOURCES: PubMed, PsycINFO, and the Cochrane Library databases were searched from January 1980 through March 2009, along with references from meta-analyses and reviews. STUDY SELECTION: Randomized placebo-controlled trials of antidepressants approved by the Food and Drug Administration in the treatment of major or minor depressive disorder were selected. Studies were included if their authors provided the requisite original data, they comprised adult outpatients, they included a medication vs placebo comparison for at least 6 weeks, they did not exclude patients on the basis of a placebo washout period, and they used the Hamilton Depression Rating Scale (HDRS). Data from 6 studies (718 patients) were included. DATA EXTRACTION: Individual patient-level data were obtained from study authors. RESULTS: Medication vs placebo differences varied substantially as a function of baseline severity. Among patients with HDRS scores below 23, Cohen d effect sizes for the difference between medication and placebo were estimated to be less than 0.20 (a standard definition of a small effect). Estimates of the magnitude of the superiority of medication over placebo increased with increases in baseline depression severity and crossed the threshold defined by the National Institute for Clinical Excellence for a clinically significant difference at a baseline HDRS score of 25. CONCLUSIONS: The magnitude of benefit of antidepressant medication compared with placebo increases with severity of depression symptoms and may be minimal or nonexistent, on average, in patients with mild or moderate symptoms. For patients with very severe depression, the benefit of medications over placebo is substantial.
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Also:
This is an excerpt from a reply to the Newsweek article to be found in Psychiatric Times. The whole article might be worth a look at.
http://www.psychiatrictimes.com/home/content/article/10168/1520550
"Furthermore, placebo group response rates in depression studies have been mysteriously and substantially rising in recent decades"
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- Scott
The measure of achievement lies not in how high the mountain,
but in how hard the climb.The measure of success lies only in how high one feels he must
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poster:SLS
thread:946874
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