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Alex Belser, PhD

Dr. Alex Belser is a psychedelic researcher and psychologist at Yale University.  For the last 20 years, he has been a leader in the psychedelic clinical community, having served as an investigator on a number of clinical trials of psilocybin and MDMA to treat depression, anxiety, substance use, OCD, PTSD, and end-of-life distress.  He is the founding President of Nautilus Sanctuary, the first non-profit center for psychedelic medicine on the east coast.  He serves as the Chief Clinical Officer of Adelia Therapeutics, a Cybin company and the third largest publicly traded psychedelic life sciences company.  Dr. Belser’s research has been featured on the front page of the New York Times, in the Atlantic, the New Yorker, The Guardian, and in Michael Pollan's book, How to Change Your Mind.

At Yale, Dr. Belser is investigating psychedelic treatments for OCD and depression.  He worked as a therapist on studies of MDMA-assisted psychotherapy for the treatment of severe PTSD.  He previously served on the Board of Advisors to Compass Pathways, then a non-profit organization.  He is a member of Chacruna Institute’s Women, Gender Diversity, and Sexual Minorities Working Group, where he works on issues affecting LGBTQI+ people.  Dr. Belser has authored over a dozen peer-reviewed journal articles and chapters and has given over fifty lectures, presentations, and Grand Rounds about psychedelic medicine. 

Dr. Belser studied at Georgetown University, the University of Cambridge, Columbia University, New York University, and Yale University.  Dr. Belser trained at Bellevue Hospital, Mount Sinai Beth Israel Hospital, and New York Psychiatric Institute at Columbia University.  He has also received extensive training in psychedelic psychotherapy from recognized senior teachers.  He is a student of somatic practices and is a licensed kundalini and hatha yoga teacher.  

His website is and his practice website is

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Willa Hall, PhD

Dr. Willa Hall received her A.B. in Psychology from UC Berkeley in 1987 and her PhD in Clinical Psychology from New School in 1999. Over the past 20 years, she has dedicated herself to raising her children while working in community mental health and private practice in New York City. In 2017 she began work on the MAPS NYC site as a co-therapist on the Phase III trials assessing the efficacy of MDMA-assisted psychotherapy for severe PTSD. Dr. Hall has a long-standing interest in understanding the ways in which the therapeutic relationship and, in particular, the therapist’s authenticity facilitates a client’s deepening appreciation of their own authentic self.  More recently, Dr. Hall’s attention has turned to understanding the therapist’s role in treatments that utilize non-ordinary states of consciousness in order to maximize growth and healing.

Emily Horowitz PsyD


Dr. Emily Horowitz is a clinical psychologist employed at the New York Veterans Affairs Medical Center, as well as in her private psychotherapy and sound healing practices. She is also a sub-investigator/study therapist for the MAPS Phase III Clinical Trial of MDMA-supported psychotherapy for the treatment of PTSD. She specializes in the treatment of depression, anxiety, PTSD, substance abuse disorders, and the integration of psychedelic and other non-ordinary-states of consciousness experiences. She graduated from Yeshiva University's Ferkauf Graduate School of Psychology in 2007.

Phil Lister, MD


Dr. Phil Lister trained in adult and child psychiatry at Weill Cornell's Payne Whitney Clinic, overlapping with training in adult and child psychoanalysis at Columbia University Center for Psychoanalytic Training and Research.  Since then he has been in private practice seeing children, adolescents, adults, and couples.  Over time, he became interested in working with families and individuals coping with bereavement, with traumatic experiences in the medical system, and with trauma more broadly defined.  He studied and incorporated EMDR and Somatic Experiencing into his practice.  Most recently he learned about and trained in psychedelic psychiatry as an extraordinary, powerful model for helping individuals heal from trauma and, more broadly, to grow into a fuller occupancy of our precious lives.

Casey A. Paleos, MD


Casey A. Paleos, MD is a psychiatrist in private practice in the New York City area, a Clinical Assistant Professor of Psychiatry at New York University, He currently serves as both Co-Principal Investigator and Study Therapist at the NYC Private Practice Site of the ongoing MAPS-sponsored Phase 3 clinical trial for MDMA-Assisted Psychotherapy for PTSD.  He is passionate about the advancement of psychedelic-assisted psychotherapy and has over 10 years of clinical experience in the field, beginning in 2009 with his work as a Study Therapist in the NYU Psilocybin Cancer Anxiety Study.  Dr. Paleos is interested in exploring the curative potential of psychedelic-assisted psychotherapy in the treatment of severe mental illness, as well as in its use for more highly functioning individuals seeking personal spiritual advancement and growth.  He views the latter usage in particular as a profoundly important vehicle for more widespread, and desperately needed, positive, grassroots societal change.