Author(s): Patrick Barry
Source: Science News, Vol. 173, No. 9 (Mar. 1, 2008), pp. 133-134
Published by: Society for Science & the Public
Stable URL: http://www.jstor.org/stable/20465258 .
Accessed: 02/09/2014 02:41
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form placebos only among extremely depressed individuals, says a team led by psychologist Irving Kirsch of the Univer sity of Hull, England. In these cases, rel atively weak placebo responses, rather than any heightened reactions to antide pressants, explain the medications' supe riority, the researchers hold.
"There is little evidence to support the prescription of antidepressant medication to any but the most severely depressed patients, unless alternative treatments with fewer side effects have failed to provide ben efit,"Kirsch says.
Alternative depression treatments with demonstrated effectiveness include physi cal exercise, several forms of psychotherapy, and even certain self-help books, in his view.
Kirsch and his colleagues obtained data from 47 clinical trials submitted to the FDA as late asMay 2007. They then weeded out
12, focusing on 35 clinical trials that typi cally lasted 6 weeks and also showed sub stantial completion rates and consistent monitoring of depression symptoms. Those trials compared randomly assigned placebo treatment to treatment with any one offour antidepressants-fluoxetine (Prozac), ven lafaxine (Effexor), nefazodone (Serzone), and paroxetine (Paxil).
A total of 5,133 depressed patients par ticipated in the clinical trials.
The researchers statistically combined data from qualifying trials and calculated the extent towhich antidepressants and place bos alleviated depression. Their findings, based on both published and unpublished data, appear in the FebruaryPLoSMedicine.
The placebo response "was exception it ally large," Kirsch says. Statistically, accounted formore than 80 percent of the symptom alleviation observed in antide pressant-treated patients. Final depression scores for patients taking antidepressants generally did not indicate any greater effects than those observed for placebo patients, Kirsch holds.
For as yet unclear reasons, the placebo effect, while it remained substantial, was weaker in the most severely depressed patients. All of the antidepressants, which belong to the newest generation of these medica tions, alleviated depression comparablywell.
Still, the FDA data are from patients with a narrow range of scores on a standard depression-rating scale, Kirsch notes. These z clinical trials focused primarily on patients
, who, at the start of treatment, scored as
E having "very severe" depression. Only a o small number of patients started out with
directed by psychiatrist Arif Khan of the
Northwest Clinical Research Center in
Bellevue, Wash. The team analyzed 52 clinical trials of depression conducted between 1985 and 2000. Antidepressants in only 25 of outperformed placebos those trials.
Clinical trials recruit a select group of patients who, typically, are seriously depressed but not suicidal and not suffer ing from other psychiatric ailments, as often happens with depressed patients seen in clinical practice, Khan asserts.