Silexan in the Treatment of Posttraumatic Stress Disorder (STOP) Trial
Collaborators: M. Berk (PI), M. Hopwood, D. Forbes, M. O’Donnell, R. Kanaan, O. Dean, M. Mohebbi, R. Khanna, G. Roebuck, W. Jensen
Funder: Congressionally Directed Medical Research Programs - $3.17 million
Key links
For more information and to participate, visit Phoenix Australia’s study landing page.
Public abstract from the funding application
Posttraumatic stress disorder (PTSD) is a common and debilitating mental illness. Current treatments for PTSD include psychotherapy and antidepressant medications. Many patients are unable to tolerate psychotherapy for PTSD and drop out of it. In addition, its effectiveness is limited. Up to 50% of patients who receive psychotherapy do not benefit from it. Antidepressant medications have only small benefits in PTSD. They also have unpleasant side effects that can make patients unwilling to take them. There is an urgent need to develop new treatments for PTSD that are effective and well- tolerated.
Silexan is a lavender oil derivative. It is taken orally in the form of capsules. It is currently available over-the-counter in Australia and the United States. Previous research has shown that it is an effective treatment for anxiety disorders, including Generalized Anxiety Disorder. It is also well-tolerated by patients. The only side effects that have been identified so far are mild gastrointestinal symptoms and these are uncommon. The results of a small pilot study suggest that Silexan may also be effective and well-tolerated in PTSD.
The STOP trial is a clinical trial that aims to investigate whether adding Silexan to treatment-as-usual improves PTSD symptoms in adults with PTSD. The trial will recruit 156 participants. Participants will take Silexan or a placebo daily in addition to their usual medications for 12 weeks. The severity of their PTSD symptoms will be assessed prior to and at the end of this 12-week period. The trial will begin in July 2023. It is expected to take 4 years for the data to be collected and analyzed and the results of the trial to be published.
The research team for the STOP trial includes an Australian Army Veteran with lived experience of PTSD. This Veteran served in the Australian Army for many years and was deployed during the Iraq War. He developed PTSD as a result of his experiences in Iraq. He has provided input into the design of the trial. He will chair a committee called the Community Advisory Board (CAB). The CAB will also include a second person with lived experience of PTSD and two psychiatrists. The role of the CAB will be to provide input and feedback to the research team from a lived experience perspective. It will meet regularly with the research team. It will also help the team to translate their findings into improved care for serving military members and Veterans with PTSD and other people suffering from PTSD.
The STOP trial addresses sub-area 3a of the FY22 TBIPHRP CTA Focus Areas because it is a clinical trial of an intervention for PTSD. The trial has the potential to obtain definitive evidence regarding the effectiveness of Silexan in PTSD. If Silexan is found to be an effective treatment for PTSD, the pool of patients who could potentially benefit from this treatment includes any adults with PTSD. Silexan is already available over the counter at a relatively low cost, so there will be few barriers to patients accessing this treatment.
Serving military members and Veterans are at high risk of developing PTSD. Nearly one-quarter of Iraq War Veterans suffer from PTSD. PTSD is an important contributing factor to the high rates of disability experienced by Veterans and their elevated risk of suicide. Existing treatments for PTSD have significant limitations. Silexan has the potential to provide an important alternative treatment for serving members and Veterans with PTSD.