Generalised Anxiety Disorder

PSI-GAD Generalised Anxiety Disorder


Incannex, in partnership with the Clinical Psychedelic Research Lab at Monash University, are investigating the use of psilocybin assisted psychotherapy to treat of Generalised Anxiety Disorder (GAD).

Program overview

In 2020, Incannex partnered with Monash University to conduct a phase 2 clinical trial to assess psilocybin-assisted psychotherapy to treat patients with generalised anxiety disorder (GAD), a unique and proprietary form of therapy called PsiGAD.
In 2021, Incannex received approval from the Monash University human research ethics committee to commence the phase 2 proof of concept PsiGAD clinical trial in 72 participants.
Led by Dr Paul Liknaitzky, Head of Clinical Psychedelic Research at Monash University, the trial is the first in the world to examine the safety and efficacy of psilocybin for any primary anxiety disorder. The trial is well-controlled (triple-blind, active placebo), and includes a range of treatment innovations alongside the development of a specialised therapist training program.
To date, more than 45 participants have been enrolled in the trial, with at least 29 participants having now completed the treatment protocol and main outcome assessment following treatment. Interim analysis of the study data, conducted by an independent Data Safety Monitoring Board (‘DSMB’) comprising experts who are not part of the trial, has commenced. The complete trial is anticipated to conclude in 2H 2023.
Treatment of GAD with standard of care antidepressant medications and therapies remains inadequate, with less than half of patients achieving remission. Psilocybin-assisted psychotherapy has shown promise in the treatment of several other mental health conditions.
The PsiGAD trial is designed to assess the safety and efficacy of the Company’s unique psilocybin program in an active placebo-controlled study. The 10-week treatment program includes two dosing sessions with either psilocybin or active placebo. Safety, efficacy, quality of life, and other aspects of mental and physical health are assessed.
Generalised Anxiety Disorder
Generalised Anxiety Disorder (GAD) is characterised by excessive anxiety and worry that occurs more days than not for at least 6 months, and is not restricted to any particular environmental circumstances. Symptoms are variable, including feelings of persistent and excessive worry, nervousness, restlessness, difficulty concentrating, and a range of somatic manifestations. People with GAD find it difficult to control their worry, which may cause significant distress and impairment in social, occupational, or other areas of functioning. GAD is a relatively common disorder (about 6-9% lifetime prevalence, and about 3% 12-month prevalence in countries like Australia and the United States). As with other mood disorders, successful treatment of GAD remains inadequate, with less than half of patients achieving remission following evidence-based treatment, alongside high relapse rates, and substantial treatment side-effects or cost.
Monash University
Monash will sponsor the trial, ensuring rigorous scientific independence and the highest standards in ethical and safe research. Monash is one of Australia’s leading universities and ranks among the world’s top 100. The treatment will be delivered within BrainPark (photos presented in Appendix 1), a state-of-the-art research platform at Monash’s Turner Institute for Brain and Mental Health and Biomedical Imaging Facility, that provides a highly conducive environment for this treatment approach in a research context. Both the School of Psychological Sciences within the Turner Institute for Brain and Mental Health, and the Department of Psychiatry within the School of Clinical Sciences, will combine forces to conduct this innovative trial, and the team will be comprised of leading researchers and clinicians in relevant fields of psychiatry, psychotherapy, and mental health treatment development.
Chief Principal Investigator – Dr Paul Liknaitzky
Dr Paul Liknaitzky works as a Research Fellow at Monash University and has Adjunct or Honorary appointments at St Vincent’s Hospital, Macquarie University, Deakin University, and the University of Melbourne. He earned an Honours in Neuroscience and a PhD in Psychology from the University of Melbourne. His work examines mechanisms of mental illness and treatment development, primarily within mood disorders and addiction research. Dr Liknaitzky is Principal Investigator across a number of Australia’s first clinical psychedelic trials. He is currently establishing a rigorous program of research in psychedelic medicine at Monash University that seeks to evaluate therapeutic effects, innovate on treatment design, mitigate known risks, explore potential drawbacks, and understand therapeutic mechanisms.

Addressable Market

  • Global market for GAD is predicted to reach USD $ 7.5 billion by 2023 (13)



Incannex is currently undertaking a phase 2 proof of concept clinical trial assessing the safety and efficacy of its own PsiGAD psilocybin-assisted psychotherapy in 72 trial participants. The 10-week treatment program includes two dosing sessions with either psilocybin or active placebo.
The Company has had a pre-IND meeting with the US FDA to discuss its development plan. Both the written responses and the responses provided in the teleconference with the FDA were positive, constructive, and supportive of PsiGAD therapy.
The FDA has provided guidance on Inannex’s long-term development strategy with regards to what will be required for a successful NDA (FDA approval) and marketing authorisation.
Specific feedback from the FDA on the Company’s proposed clinical trial designs have played an important role in shaping the design of a planned phase 2b PsiGAD clinical trial, which will be the IND opening study, following the conclusion of the PsiGAD proof of concept trial that is currently underway.
Change to classification of psilocybin in Australia
From 1 July 2023, medicines containing psilocybin can be prescribed by specifically authorised psychiatrists for the treatment of treatment-resistant depression. This is considered by the Australian Therapeutic Goods Association (TGA) to be the only condition whereby there is sufficient evidence for potential benefits in certain patients. Incannex is assessing an application to TGA for PsiGAD therapy to be included in the authorised prescriber scheme for psilocybin.