This paper shows that negative results of trials are often withheld, when the results of drugs are
completely random compared to placebo this can make the drug appear to be working.
Selective Publication of Antidepressant 
Trials and Its Influence on Apparent Efficacy
Erick H. Turner, M.D., Annette M. Matthews, M.D., Eftihia Linardatos, B.S., 
Robert A. Tell, L.C.S.W., and Robert Rosenthal, Ph.D.
From   the   Departments   of   Psychiatry 
(E.H.T.,    A.M.M.)    and    Pharmacology 
(E.H.T.), Oregon Health and Science Uni
-
versity;  and  the  Behavioral  Health  and 
Neurosciences  Division,  Portland  Veter
-
ans Affairs Medical Center (E.H.T., A.M.M., 
R.A.T.) 
— 
both in Portland, OR; the De
-
partment of Psychology, Kent State Uni
-
versity, Kent, OH (E.L.); the Department 
of  Psychology,  University  of  California–
Riverside,  Riverside  (R.R.);  and  Harvard 
University, Cambridge, MA (R.R.). Address 
reprint requests to Dr. Turner at Portland 
VA  Medical  Center,  P3MHDC,  3710  SW 
US  Veterans  Hospital  Rd.,  Portland,  OR 
97239, or at turnere@ohsu.edu.
N Engl J Med 2008;358:252-60.
Copyright © 2008 Massachusetts Medical Society.
A B S T R A C T
BACKGROUND
Evidence-based medicine is valuable to the extent that the evidence base is complete 
and unbiased. Selective publication of clinical trials — and the outcomes within 
those trials — can lead to unrealistic estimates of drug effectiveness and alter the 
apparent risk–benefit ratio.
METHODS
We obtained reviews from the Food and Drug Administration (FDA) for studies of 
12 antidepressant agents involving 12,564 patients. We conducted a systematic lit
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erature search to identify matching publications. For trials that were reported in the 
literature, we compared the published outcomes with the FDA outcomes. We also 
compared the effect size derived from the published reports with the effect size de
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rived from the entire FDA data set.
RESULTS
Among 74 FDA-registered studies, 31%, accounting for 3449 study participants, were 
not published. Whether and how the studies were published were associated with 
the study outcome. A total of 37 studies viewed by the FDA as having positive results 
were published; 1 study viewed as positive was not published. Studies viewed by the 
FDA as having negative or questionable results were, with 3 exceptions, either not 
published (22 studies) or published in a way that, in our opinion, conveyed a posi
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tive outcome (11 studies). According to the published literature, it appeared that 
94% of the trials conducted were positive. By contrast, the FDA analysis showed that 
51% were positive. Separate meta-analyses of the FDA and journal data sets showed 
that the increase in effect size ranged from 11 to 69% for individual drugs and was 
32% overall.
CONCLUSIONS
We cannot determine whether the bias observed resulted from a failure to submit 
manuscripts on the part of authors and sponsors, from decisions by journal editors 
and reviewers not to publish, or both. Selective reporting of clinical trial results may 
have adverse consequences for researchers, study participants, health care profes
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sionals, and patients
