We recently concluded a heated debate on whether anti- depressants are truly effective relative to placebo, with recent research claiming that they are not both supported and disputed by TIPSters.
Here's another possibility to explain why anti-depressants tend not to do well in placebo-controlled trials (unless you take the position that they in fact are effective relative to placebo and studies showing otherwise are shoddy and forgettable). Placebos are getting stronger. In other words, the failure of anti- depressants to show benefit relative to placebo is not due to poorer performance of the drugs, but to improved performance of placebos. This, I guess, is good news, although not necessarily for the drug industry. A new (and yet another) meta-analysis of anti-depressant response vs placebo reports this as one of its findings. Rief et al (2009) found that "the effect sizes in placebo groups in 2005 were more than twice as great as those in 1980", indicating a substantial increase in placebo effectiveness. But note that this was only for observer ratings rather than for patient reports. An interesting question is why. Possibly patients have greater confidence in the anti-depressant cure these days but, if this was the reason, one would expect that the effect would also occur for patient reports, probably to an even greater extent. National Public Radio in the U.S. has an article on the finding here: http://www.npr.org/templates/story/story.php?storyId=12436705 8 or http://tinyurl.com/yfmkauy The growing power of the sugar pill (March 8, 2010) Source: Rief, W. et al (2009). Meta-analysis of the placebo response in antidepressant trials. Journal of Affective Disorders, 118, 1-8. Stephen -------------------------------------------- Stephen L. Black, Ph.D. Professor of Psychology, Emeritus Bishop's University e-mail: sblack at ubishops.ca 2600 College St. Sherbrooke QC J1M 1Z7 Canada ----------------------------------------------------------------------- --- You are currently subscribed to tips as: [email protected]. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13090.68da6e6e5325aa33287ff385b70df5d5&n=T&l=tips&o=1156 or send a blank email to leave-1156-13090.68da6e6e5325aa33287ff385b70df...@fsulist.frostburg.edu
