The study "Long-term Follow-up Outcomes of MDMA-assisted Psychotherapy for Treatment of PTSD: A Longitudinal Pooled Analysis of Six Phase 2 Trials" has been retracted by the journal Psychopharmacology in January 2020. The retraction comes after the discovery of protocol violations at one of the study sites (MP4) and the failure of the researchers to disclose these violations to the journal or remove data from the compromised site in their analysis.

The original study aimed to evaluate the long-term outcomes of MDMA-assisted psychotherapy for the treatment of post-traumatic stress disorder (PTSD). The study reported significant reductions in PTSD symptom severity that were sustained at long-term follow-up, with 67% of participants no longer meeting PTSD diagnostic criteria at the final assessment. These findings had the potential to inform future research and clinical practice in the field of psychedelic-assisted psychotherapy for mental health conditions.

The retraction notice, published in Psychopharmacology, cites "protocol violations amounting to unethical conduct" at the MP4 study site. However, specific details about the nature of these ethical violations have not been provided.

In addition to the protocol violations, the authors failed to fully declare potential conflicts of interest. Several authors are affiliated with the Multidisciplinary Association for Psychedelic Studies (MAPS) or its wholly-owned subsidiary, MAPS Public Benefit Corporation (MAPS PBC). MAPS funded the study and provided the MDMA used in the trials, while MAPS PBC organized the study.

The retraction has elicited mixed responses from the authors. Allison A. Feduccia agrees with the retraction but disagrees with the wording of the notice. Michael C. Mithoefer, Lisa Jerome, Berra Yazar-Klosinski, and Rick Doblin oppose the retraction, while the remaining authors did not respond to correspondence from the publisher.

This retraction emphasizes the importance of adhering to ethical guidelines, disclosing potential conflicts of interest, and maintaining transparency in research. The inclusion of data from the compromised site and the lack of disclosure of conflicts of interest raise concerns about the validity and reliability of the study's findings.

The retraction of this study may have implications for future research on MDMA-assisted psychotherapy for PTSD and highlights the need for strict compliance with ethical standards and transparent reporting of conflicts of interest. Given the retraction, replication studies and further research in this field will be crucial to establish the efficacy and safety of MDMA-assisted psychotherapy for PTSD.

For more information, please refer to the following resources:

• Original study: https://doi.org/10.1007/s00213-020-05548-2
• Retraction notice: https://doi.org/10.1007/s00213-024-06665-y