Discontinuation of medications classified as reuptake inhibitors affects treatment response of MDMA-assisted psychotherapy

Introduction

Feduccia and colleagues frame the study within ongoing investigations of MDMA-assisted psychotherapy as a treatment for post-traumatic stress disorder (PTSD). Earlier phase 2 trials demonstrated large between-group reductions in CAPS‑IV PTSD severity for participants receiving active MDMA (75–125 mg) plus manualised psychotherapy compared to control doses, and MDMA is known to increase synaptic serotonin, norepinephrine, and dopamine via reversal of transporter proteins (SERT, NET, DAT). Because many commonly prescribed antidepressant medications for PTSD (SSRIs, SNRIs, NRIs, NDRIs) act on the same reuptake transporters, prior studies have shown that co-administration or recent use of such drugs can attenuate MDMA's subjective and physiological effects, and participants in the phase 2 trials were required to taper off psychiatric medications before MDMA sessions to minimise interactions and withdrawal effects. This paper pools data from four phase 2 randomized, double-blind trials to explore whether recent tapering off medications classified as reuptake inhibitors affected clinical and physiological responses to active MDMA-assisted psychotherapy. The investigators compared PTSD severity (CAPS‑IV), depression symptoms (BDI‑II), and peak vital signs during MDMA sessions between participants who had tapered off reuptake inhibitors prior to blinded sessions (taper group) and those who had not been taking such medications at screening (non-taper group). The intent was to assess whether recent exposure to reuptake inhibitors blunts treatment response to MDMA-assisted psychotherapy and to characterise any related physiological differences.