Posted by Larry Hoover on February 9, 2003, at 17:13:31
In reply to Anti_depressants little more than placebos?, posted by fuzzymind on February 9, 2003, at 16:35:58
> I have read some recent articles suggesting that anti depressants are only marginally more effective than placebos, and the efficacy of the drugs during trials is heavily manipulated.
The most comprehensive meta-analysis of the FDA database of clinical trials was conducted by Dr. Khan. Unfortunately, he is frequently misquoted and misinterpreted.
With respect to the former assertion, I've presented the data below. The latter assertion is false.
>During trials, apparently they give placebos first, then eliminate those test subjects who are affected by the placebos, thus sever3ely skewing the results.
That's simply not true. That would not be double-blind.
>ALos, double blind tests are not necessarily used.
Open trials cannot be used for the purpose of determining efficacy with respect to FDA approval. However, open trials are often used to obtain preliminary evidence of efficacy.
> I had taken about 7=8 different anti-D's, with no results, except drowsiness. One gave me hives.That sucks. I'm sorry to hear that.
About placebo groups in clinical trials:
Placebo groups in clinical trials are not untreated. This is a common misconception among both medical practitioners and laypeople, alike.
Seattle psychiatrist Arif Khan found that in 52% of the trials, the effect of the drug could not be distinguished from the placebo.
http://education.guardian.co.uk/higher/research/story/0,9865,740721,00.htmlFrom http://www.psychiatrictimes.com/p000429.html, written by Khan himself:
"Altogether, 8,731 depressed patients participated in 45 pivotal clinical trials. Of these, 4,510 were assigned to the investigational antidepressants, 1,416 to established antidepressants (imipramine [Tofranil], amitriptyline [Elavil, Endep] or trazodone [Desyrel]) and 2,805 to placebo. Statistical analysis indicated that all of the antidepressants were significantly superior to placebo in decreasing the HAM-D score total. Of note was the positive relationship between duration of clinical trial and reduction of symptoms: the longer the duration of the clinical trial, the greater the decrease in depressive symptoms, regardless of treatment. Among the placebo-treated patients, the reduction in mean total HAM-D scores was 24.7% in four-week trials, 31.5% in five-week trials, 30.5% in six-week trials and 36.1% in eight-week trials. Correspondingly, the reduction with traditional antidepressants was 28.2% in four-week trials, 44% in six-week trials and 48.1% in eight-week trials. The reduction with investigational antidepressants was 40% in four-week trials, 40.5% in five-week trials, 40.6% in six-week trials and 43.9% in eight-week trials (Khan et al., in press). "
**Note this next paragraph, please. Placebo subjects are not untreated.**
"The less-than-impressive results in these and other studies also calls to mind the fact that patients assigned to placebo treatment in clinical trials are not "getting nothing." The capsule they receive is pharmacologically inert but hardly inert with respect to its symbolic value and its power as a conditioned stimulus. In addition, placebo-treated patients receive all of the commonly employed treatment techniques: a thorough evaluation; an explanation for their distress; an expert healer; a plausible treatment; expectation of improvement; a healer's commitment, enthusiasm and positive regard; and an opportunity to verbalize their distress. "
He goes on to include a very important warning about the interpretation of his findings:"A cautionary note is indicated about the generalization of these data to the clinical management of depressed patients. The less-than-impressive difference between drug and placebo in this and other studies of clinical trials does not speak directly to the effectiveness of antidepressants in clinical practice. Participants in antidepressant clinical trials are a highly select group and are not representative of the general population of depressed patients. They are not actively suicidal, they are almost always outpatients who are moderately rather than severely or mildly depressed, and they are free of comorbid physical or psychiatric illness. They are likely to have a higher placebo response rate than more severely ill depressed patients. "
"Furthermore, the primary aim of these studies is not to assess the optimal effect of antidepressants, but rather to rapidly assess efficacy of new drugs so they can be brought to the market. Therefore, dose, duration and diagnosis in clinical trials are not necessarily ideally suited to identify the optimal effects of antidepressants. Accordingly, clinical trials may identify the lower bound of the effect size compared to placebo. "
poster:Larry Hoover
thread:140316
URL: http://www.dr-bob.org/babble/20030208/msgs/140324.html