Too big to fail? Comparing effect sizes of MDMA assisted therapy to unmasking bias
Balazs Szigeti, Ellen Bradley, Joshua Woolley
preprint DOI: 10.31219/osf.io/ujtpf
Summary
The FDA rejected MDMA-assisted therapy for PTSD, citing concerns over unmasking bias in trials. The analysis reveals that unmasking bias is greater than the effect size of treatment versus control for MDMA, although it does not confirm that the effects are solely due to this bias. The findings suggest that the observed effect sizes for MDMA-AT could be influenced by unmasking.
Study at a glance
| Key finding | Unmasking bias is larger than the treatment versus control effect size for MDMA, indicating that MDMA-AT’s effect sizes could be influenced by this bias. |
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Abstract
On August 9th the US Food and Drug Administration’s (FDA) rejected 3,4-methylenedioxymethamphetamine assisted therapy (MDMA-AT) as a treatment for post-traumatic stress disorder (PTSD), despite seemingly positive trial results. A major reason cited was functional unmasking, which combined with enthusiasm about MDMA, raised concerns about the objectivity of these trials. Here, we define what is 'unmasking bias' and calculate its magnitude for two drugs, ketamine and escitalopram, where data was available from the literature. Our results show that unmasking bias is larger than the treatment vs control effect size for MDMA. These findings do not prove that effects of MDMA-AT are entirely or even partially due to unmasking, however, our findings do indicate that MDMA-AT’s effect sizes are not too large to be due to unmasking.