Statement: Public Announcement of Ethical Violation by Former MAPS-Sponsored Investigators

We encourage you to read and follow for detailed information regarding MAPS Code of Ethics for Psychedelic Psychotherapy and our practices to create a culture of safety in psychedelic therapy. 

You may safely and confidentially direct misconduct reports related to MAPS-sponsored studies, MAPS staff, MAPS PBC staff, or collaborators to MAPS’ Compliance Team via email or by calling (844) 627-7722.

Updated announcement March 25, 2022*

This is a public announcement of additional information obtained regarding the conduct of former sub-investigators for a MAPS-sponsored clinical trial, initially publicly reported in 2019. We make this information public as part of our commitment to creating a culture of safety in psychedelic therapy and in alignment with our core value of transparency. 

The initial ethics complaint was reported to MAPS in 2018 by the participant. The complaint specifically identified the unethical conduct as occurring after the active treatment sessions had concluded in 2015. Yensen and former sub-investigator Donna Dryer verbally confirmed that Yensen engaged in a sexual relationship with the participant. Sexual contact between therapy providers and participants is unethical conduct of sexual abuse in violation of Section 6 of MAPS Code of Ethics for Psychedelic Psychotherapy and generally accepted standards of care. In 2018, as a result of the ethical misconduct, Yensen and Dryer were barred from all MAPS-related activities and from becoming providers of MAPS-affiliated MDMA-assisted therapy if the treatment is approved.

On Saturday, November 6, 2021, MAPS staff were interviewed by a reporter who had viewed videos of clinical trial therapy sessions for the participant described in the original announcement below. Session video is made available to participants in MDMA-assisted therapy clinical trials for private review upon request. The reporter characterized former sub-investigator Richard Yensen’s behavior in at least one therapy session as “disturbing.” This characterization triggered a compliance review which was initiated Monday, November 8, 2021. 

The reopened review of conduct during the trial period includes a review of previous documentation, all available videos of sessions from the sub-investigators, and information reported in media accounts of the participant’s experience. Though the review is ongoing, MAPS has provisionally determined that Yensen and Dryer substantially deviated from the MDMA-assisted Therapy Treatment Manual on several occasions during the treatment period. 

MAPS has notified the U.S. Food and Drug Administration (FDA), Health Canada,  Ethics Committees, and relevant authorities that the review has been re-opened. We will continue to keep regulatory agencies, ethics committees, and relevant authorities apprised of any developments on this case. Changes to MAPS policies, practices, or materials made as the direct result of the review will be reported publicly at

Original announcement May 24, 2019

This message is a public announcement of ethical violations committed by former sub-investigators who previously provided therapy on a MAPS-sponsored clinical trial. The contents of this message may be potentially triggering to those who have been subject to ethical violations and trauma of a sexual nature. We intend our making this information public to be part of our effort to eliminate future ethical violations by these and any other prior, current, or future therapists working for MAPS.

A summary of the violation is below:

A female participant was enrolled in the study on December 23, 2014, completed active treatment in the study on October 7, 2015, and terminated from the study at the Long Term Follow Up visit on June 16, 2016. The participant’s co-therapists were Richard Yensen, Ph.D., and Dr. Donna Dryer, a married couple.

In June 2015, the participant moved to where the two therapists live. The participant continued to receive therapy from her therapists during this time and completed her Long Term Follow Up visit. At the end of 2015 or early 2016, the relationship between Richard Yensen and the participant became sexual in nature. Donna Dryer reportedly became aware of this and tried to stop the sexual relationship but was unsuccessful. She did not report it to MAPS or any regulatory agencies. Over time, the participant grew uncomfortable with this relationship and eventually moved away in early 2017, breaking ties with both therapists.

In January 2018, the participant submitted complaints naming both Richard Yensen and Donna Dryer to the College of Psychologists of British Columbia and the BC College of Physician and Surgeons. On October 15, 2018, the participant forwarded the complaints to MAPS Public Benefit Corporation (MAPS PBC). The complaints were related to inappropriate and unethical sexual involvement with Richard Yensen. Prior to this notification, MAPS and MAPS PBC were not aware of this complaint or any inappropriate interaction between study subjects and therapists. Monitoring of study records throughout the course of the trial and afterwards did not indicate signs of ethical violation.

Shortly after receiving the complaint in October 2018, MAPS PBC submitted reports to the US FDA, Health Canada and the ethics review committee. During this period, Richard Yensen and Donna Dryer verbally confirmed to MAPS that this sexual relationship did occur.

MAPS has policies in place that forbid sexual relationships between therapists and patients. There was no prior indication that Richard Yensen or Donna Dryer would violate this policy. MAPS’ legal counsel concluded that the therapists bore legal responsibility for their actions and that MAPS itself was not liable. MAPS agreed on a compassionate basis to pay $15,000 Canadian to the study participant so that she could afford to obtain therapy while her legal action against the therapists seeking compensation from them was still in process.

As the Sponsor, we take this situation very seriously. MAPS and MAPS PBC will not be working with either therapist in the future. The safety of study participants is our priority. The treatment of people experiencing trauma deserves the highest quality of care. The nature and integrity of professional therapeutic relationships must be attended to and protected. The protective measures in place include having two therapy providers in every therapy visit, video recording of all therapy visits, monitoring of study and therapy activities, and clinical supervision. In this case, none of these measures were sufficient.

MAPS PBC has recently published a formalized Code of Ethics. This Code is now being incorporated into the MDMA Therapy Training Program, with training curriculum and presentations about ethical issues in this work. Every current and incoming study staff member is being oriented on this Code and required to sign their agreement to act in accordance with the Code. Further structures to enforce the code, such as a Patients’ Bill of Rights, a formal grievance process, supportive resources for those who file a grievance, and designated internal review committee, are in development.

We welcome your questions and comments at, though we regret that we won’t be able to respond to every message.

We also encourage you to learn more about MAPS and MAPS PBC’s commitment to ethical integrity in psychedelic therapy in the MAPS Bulletin:


Founded in 1986, MAPS is a 501(c)(3) non-profit research and educational organization that develops medical, legal, and cultural contexts for people to benefit from the careful uses of psychedelics and marijuana. For more information, visit

MAPS-sponsored clinical trials are conducted by the MAPS Public Benefit Corporation (MAPS PBC), a wholly owned subsidiary of MAPS formed in 2014 for the special purpose of balancing social benefits with income from legal sales of MDMA, other psychedelics, and marijuana. For more information, visit

* March 25, 2022 5:51pm Pacific Time: The update to this statement was initially dated for May 2022 and then March 24, 2022. This was a typo and the date was corrected March 25, 2022.