Intense interest in psychedelic-assisted psychotherapy has been sparked over the last five years, as promising results of Phase 2 and 3 clinical trials reaffirm the potential for psychedelics to aid in the treatment of a range of mental health conditions.

Historically, the “natural” classical psychedelics - psilocybin, mescaline and LSD - were employed as adjuncts to psychotherapy for the treatment of alcoholism and mood disorders such as anxiety and depression. More recently, DMT in ayahuasca has generated interest for its therapeutic potential.

Reflecting the extended duration of LSD and mescaline at therapeutic doses, but more significantly, the troubled sociopolitical history of LSD, the current “psychedelic renaissance” has largely been led by psilocybin, which (along with DMT) is the prototypic serotonin receptor agonist with psychedelic effects.

The primacy of psilocybin in clinical use may, however, be short-lived, as the range of serotonin 5HT2A receptor agonists that elicit psychedelic experiences is broad (and set to expand as research in psychedelic chemistry is revitalised), and the range of experiences they elicit is almost as diverse. Ultimately, it appears likely that an increasingly nuanced approach to the use of psychedelics in medicine will see the searchlight casting well beyond its current narrow focus.

In this presentation, I will discuss the current emphasis on psilocybin as the psychedelic of choice for clinical research, and then consider the potential for a broad range of other classical psychedelics – from 2C-B to AMT - to play important roles in future research and, ultimately, clinical practice.


Martin Williams, PhD, is a research fellow in Medicinal Chemistry at the Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne. He is founding and current President of the DGR-registered health-promotion charity, Psychedelic Research in Science & Medicine (PRISM), founding and current Vice-President of the botanical/education charity, Entheogenesis Australis (EGA), and co-lead investigator of the upcoming Melbourne psilocybin trials at St Vincent’s Hospital.

Through PRISM, Martin and his colleagues have been advocating since 2011 for mental health research using psychedelic compounds in Australia, and in doing so, have established connections with researchers in the USA, Canada, the Czech Republic, Germany, the Netherlands, New Zealand and the United Kingdom. In the course of planning and seeking approvals for two clinical trials, one of MDMA-assisted psychotherapy for the treatment of PTSD and the other of psilocybin-assisted psychotherapy for the treatment of anxiety and depression associated with terminal illness, Martin has become familiar with the Australian regulatory and research governance landscape.

Martin and the Palliative Care team at St Vincent’s Hospital, Melbourne, recently achieved the requisite Human Research Ethics and state and federal government approvals for their proposed Phase 2 psilocybin trial, which began in late January 2020. He is currently working with another interdisciplinary research group on plans for a clinical trial of psilocybin-assisted psychotherapy for treatment-resistant depression.

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