Unpublished Trials Reveal Antidepressant Provides Little Benefit For Depression or Anxiety

Rob Wipond

Upon reviewing all of GlaxoSmithKline’s data from both published and unpublished trials of the antidepressant paroxetine, researchers found the drug provided almost no benefits over placebo for either depression or anxiety, according to a study in PLOS One.

The Wayne State University researchers, in collaboration with Harvard’s Irving Kirsch, stated that evaluating the efficacy of antidepressant medications on depression and anxiety has until now been hampered by a lack of access to pharmaceutical companies’ unpublished trials. “Here, for the first time, we assess the efficacy of a selective serotonin reuptake inhibitor (SSRI) in the treatment of both anxiety and depression, using a complete data set of all published and unpublished trials sponsored by the manufacturer.”

They found that the published literature tended to overestimate the efficacy of the drug, and overall the drug provided tiny benefits of only 2-3 points on common rating scales for depression and anxiety — much of which was due to placebo effects. “The available empirical evidence indicates that paroxetine provides only a modest advantage over placebo in treatment of anxiety and depression,” they wrote. “We demonstrated that individuals given placebo exhibited 79% of the magnitude of change compared to paroxetine.”

“These findings have important clinical implications,” the researchers commented. “The obvious alternative for the treatment of both anxiety and depression is psychotherapy intervention. However, direct comparisons of acute phase treatment for pharmacotherapy and psychotherapy in the treatment of major depression generally have yielded no significant differences between the treatment modalities. Fewer clinical trials have directly compared antidepressants and psychotherapy in the treatment of anxiety disorders, although the available literature indicates similar comparability between antidepressants and psychotherapy.”

The Efficacy of Paroxetine and Placebo in Treating Anxiety and Depression: A Meta-Analysis of Change on the Hamilton Rating Scales (Sugarman, Michael A. et al. PLOS One. August 27, 2014. DOI: 10.1371/journal.pone.0106337)

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Rob Wipond
Rob Wipond is a Victoria, British Columbia-based freelance journalist who has been writing on mental health issues for fifteen years. His research has particularly focused on the interfaces between psychiatry, the justice system, and civil rights. His articles have been nominated for three Canadian National Magazine Awards, six Western Magazine Awards, and four Jack Webster Awards for journalism. He can be contacted through his website.


  1. Oh, so the trials Glaxo published show the drugs might work, but the trials they didn’t publish show the drugs don’t work ?

    Funny that.

    But why are those responsible not accountable ? Imagine if the penalty for getting caught commiting any crime was that the perpetrator simply had to promise not to do it again.