The study showed that in comparison to placebo effects, antidepressants do not have clinically significant effects in mildly depressed patients or in most patients who suffer from very severe depression. The study also claimed that the minor percentage of clinical effectiveness of antidepressants noticed in the small group of extremely depressed patients was due to the fact that these patients’s response to the placebo decreased, rather than any notable increase in their response to antidepressants.
The study results were reported after a meta-analysis of both published and unpublished data from clinical trials of four selective serotonin reuptake inhibitors – Bristol-Myers Squibb’s drug Serzone (nefazodone), GlaxoSmithKline’s Paxil/Seroxat (paroxetine), Wyeth’s Effexor (venlafaxine) and Eli Lilly’s Prozac (fluoxetine). But major drugmakers GSK and Lily disagreed with the study results and defended their anti-depressant drugs.
Mr. Kirsch said: “The difference in improvement between patients taking placebos and patients taking antidepressants is not very great. This means that depressed people can improve without chemical treatments.”