Silexan in the Treatment Of Posttraumatic Stress Disorder Trial

Recruiting now · Phase 3 · Has a placebo group

Conditions studied: Post Traumatic Stress Disorder

In brief

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 percent 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 work and are well-tolerated. Silexan has the potential to provide an important alternative treatment for PTSD. Silexan is derived from lavender oil. It is taken orally in the form of capsules. It is currently available over-the-counter in 14 countries, including 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 (including burping and breath odour) 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 278 participants. Participants will be randomly assigned to take Silexan or a placebo (look-alike dummy pills) 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 STOP trial has the potential to obtain definitive evidence regarding whether Silexan helps treat symptoms of 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 accessing this treatment.

Key facts

Study ID

NCT06412757

Run by

Deakin University

People needed

278

Starts

2024-08-26

Expected to finish

2027-06-01

Last updated by the study team

2025-12-18

Who can join

Age: 18 and older. Sex: any. Healthy volunteers: not accepted.

You may qualify if…

• Aged 18 years or over.
• Fluent in English.
• Meet DSM-5 criteria for PTSD, irrespective of occupation (e.g. first responder, police officer, ex-military or civilian), determined using the Mini International Neuropsychiatric Interview 7.0.2.
• Have a score on the PTSD Checklist for DSM-5 (PCL-5) equal to or over 33.

You may not qualify if…

• Are currently serving in the Australian Defence Force
• Lifetime history of a psychotic or bipolar disorder, or dissociative identity disorder.
• Moderate or severe alcohol or other substance use disorder within 3 months of screening.
• Active suicidal or homicidal ideation.
• Borderline Personality Disorder (BPD).
• Acute or unstable medical illness or other significant medical condition, that would make participation in the trial unsafe or inappropriate.
• Pregnancy, lactation or unwillingness to use an acceptable method of contraception (required for both males and females who are of reproductive potential and sexually active with partners of the opposite sex) through the duration of participants' involvement in the study up to and including week 16. Participants will also be advised not to donate eggs or sperm during the study period.
• Commencement of a trauma-focussed psychotherapy (including Prolonged Exposure, Cognitive Processing Therapy and Eye Movement Desensitisation and Reprocessing) within 3 months of screening.
• Commencement or change in dose of psychoactive medications within 4 weeks of screening.
• Participants will be asked not to initiate psychotherapy or change the dose of psychoactive medications during the course of the study except in clinically urgent circumstances; if this becomes necessary, a decision will be made on a case-by-case basis with regard to retaining the participant or terminating their participation.
• Severe acquired brain injury.
• Individual is not eligible for public mental health services due to their visa status in Australia or for any other reason.
• Any other condition that in the opinion of the research team is likely to make completion of the trial requirements infeasible.
• Inability to understand or speak English to the extent necessary to give informed consent and complete the trial (researcher or clinician-determined).

Where it is running

• University of Melbourne — Carlton, Victoria, Australia (enrolling)
• Deakin University — Geelong, Victoria, Australia (enrolling)
• Austin Health — Heidelberg, Victoria, Australia (enrolling)
• Ramsay Clinic Albert Road — Melbourne, Victoria, Australia (enrolling)

Full record on ClinicalTrials.gov

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