Efficacy and Safety of Silexan (Lavender Oil) in Mild to Moderate Major Depressive Disorder: A Randomized, Double-Blind, Placebo-Controlled Trial
- Trial ID
- 2025-521744-37-00
- Protocol
- D.01.01.3.06
Trial statistics
Diseases & Conditions
Objectives
The primary objective is to demonstrate the superiority of 80 mg/day of Silexan versus placebo regarding the change in the Montgomery-Åsberg Depression Rating Scale (MADRS) total score from baseline to week 8 in patients with major depressive disorder of mild to moderate severity. To establish clinical relevance, the study evaluates responder and remission rates, defined as a reduction of at least 50% in the MADRS total score and a total score of less than 10 points, respectively. Secondary objectives include:
- Evaluation of efficacy through the assessment of changes in depressive symptoms, functional impairment, and global improvement.
- Assessment of safety and tolerability.
Participants
The sponsor did not provide information regarding the total number of participants. The study population consists of patients diagnosed with major depressive disorder of mild to moderate severity, as defined by the ICD-10. Eligible individuals must be at least 18 years of age and present with a major depressive episode lasting between two weeks and one year. Inclusion requires a Montgomery-Åsberg Depression Rating Scale total score between 17 and 30. Participants must be undergoing outpatient treatment and possess a body mass index ranging from 18 to 35 kg/m2. The cohort includes both male and female individuals.
Plans and Procedures
This randomised, double-blind, placebo-controlled trial is designed to evaluate the efficacy and safety of Silexan, an oral lavender oil capsule, in patients diagnosed with major depressive disorder of mild to moderate severity. The methodology involves comparing 80 mg of Silexan once daily against a placebo to demonstrate superiority regarding the change in the Montgomery-Åsberg Depression Rating Scale total score from baseline to week 8. The study procedure begins with a screening visit to assess eligibility based on criteria such as age, body mass index, and specific diagnostic codes. Following inclusion, participants undergo an active treatment phase lasting 8 weeks. Secondary efficacy endpoints include changes in the Clinical Global Impressions scale, the Patient Health Questionnaire-9, and the Sheehan Disability Scale. Safety is monitored through adverse event reporting, physical examination, vital signs, electrocardiography, and laboratory evaluation. The trial includes an end-of-study assessment to conclude the observation period.
Treatment
The experimental medication consists of Silexan, which is an 80 mg dose of lavender oil. This substance is administered in the form of a soft capsule via oral use. The prescribed frequency of administration is once daily.
The control group receives a placebo equivalent to the Silexan 80 mg administration to maintain the double-blind nature of the trial.
Efficacy
The primary efficacy endpoint is the change from baseline in the Montgomery-Åsberg Depression Rating Scale (MADRS) total score at week 8. Secondary efficacy assessments include the evaluation of responder rates, defined as a reduction of at least 50% in the MADRS total score from baseline to week 8, and remission rates, defined as a MADRS total score of less than 10 points at week 8.
Additional efficacy parameters measured at week 8 consist of:
- Changes from baseline in the Clinical Global Impressions (CGI) (Item 1), Patient Health Questionnaire-9 (PHQ-9) total score, and Sheehan Disability Scale (SDS) total score.
- The CGI (Item 2) score.
Inclusion and Exclusion Criteria
Inclusion Criteria
- Age of at least 18 years.
- Diagnosis of a major depressive episode according to ICD-10 (single episode: F32.0, 32.1, recurrent episode: F33.0, 33.1) of mild to moderate severity with a duration of at least 2 weeks but not longer than one year.
- MADRS total score for the inclusion in the run-in and into the active treatment phase: 17–30.
- Outpatient treatment by a general or specialised physician.
- Body weight: Body Mass Index (BMI) between 18 and 35 kg/m2.
- Written informed consent in accordance with the legal requirement.
- Readiness and ability on the part of the participant to comply with the physician’s instructions and to fill in the self-assessment scales.
Exclusion Criteria
- Participation in a further clinical trial at the same time or in the last 12 weeks before screening.
- History of hypersensitivity to lavender preparations and/or known allergies to the IMP, placebo or excipients.
- Any unstable acute medical disorder or clinically relevant hepatic, renal, cardiovascular, respiratory, cerebrovascular, metabolic disorder or progressive diseases as cancer, haematologic diseases (including haemophilia, Christmas disease, von Willebrand’s disease, past medical history of bleeding gastric or duodenal ulcers or other significant bleeding disorders) or thyroid insufficiency (exception: non-insulin dependent diabetes mellitus, thyroid and anterior pituitary insufficiency on stable treatment), epilepsy or a history of seizure disorder or treatment with anticonvulsants for epilepsy or seizures, Parkinson’s disease.
- Any somatic disease that necessitates regular treatment with systemic steroids.
- Clinically significant abnormality of ECG and/or laboratory value(s) assessed at Screening Visit.
- Any abnormal baseline finding considered by the investigator to be indicative of conditions that might affect trial results.
- Positive pregnancy test during Visit 1.
- Pregnancy, planning of pregnancy or lactation.
- Persons capable of childbearing if not using highly effective contraception; these include: • Oral, intravaginal, transdermal combined (oestrogen and progestogen containing) hormonal contraception • Oral, injectable and implantable progestogen-only hormonal contraception • Intrauterine device • Intrauterine hormone-releasing system • Bilateral tubal occlusion • Vasectomised partner • Sexual abstinence (referring to heterosexual relationships)
- Gastrointestinal disorders with uncertain absorption of orally administered drugs (e.g. partial or total gastrectomy, enterectomy, inflammatory bowel disease, celiac disease, symptomatic lactose intolerance, other disorders associated with chronic diarrhoea).
- Unable to read, understand and/or complete questionnaires.
- Diagnosis of MDD of severe severity as defined by ICD-10 (single episode: F32.2, recurrent episode: F33.2) or rating of the MADRS total score > 30 at screening or baseline visit.
- History or suspicion of unreliability, poor cooperation or non-compliance with medical treatment.
- Any clinically important psychiatric or neurological diagnoses according to ICD-10, other than trial indication, within 6 months before the trial such as: • Schizophrenia (F20.-), • Acute anxiety disorder (F41.-) • Episodes of depression with any characteristics of a psychotic nature (F32.3, F33.3), depressive disorders not defined as inclusion criteria (F34.1, F32.9), bipolar disorder (F31.-), cyclothymia (F34.0), mania (F30.-), • Organic, including symptomatic, mental disorders (F00-F09), • Post-traumatic stress disorder (F43.10), • Eating disorders (F50.-).
- History or evidence of alcohol and/or substance abuse or dependence, particularly of sedatives, hypnotics and anxiolytics. (F10-F19).
- Risk of suicide, or previous suicide attempt or clear display of auto-aggressive behaviour as defined (but not limited to) MADRS Item 10 “suicidal thoughts” score 2.
- Lack of response to any adequate antidepressant therapy in the present episode of depression (adequate means 150 mg amitriptyline-equivalents per day or SSRI treatment during at least 6 weeks). Patients who are already well adjusted to an antidepressant therapy in the present episode may not be enrolled into this trial.
- Any of the following treatments within 30 days before baseline visit: • Antidepressants • Depot neuroleptics • Monoamine oxidase (MAO) inhibitors •Pimozide •Benzodiazepines •Other psychotropic drugs •Intravenous methylene blue •Linezolid.
- Unacceptability to discontinue or likelihood to need medication during the trial that is prohibited as concomitant treatment (see section 10.2). The following medication is not allowed during the trial: • Any psychotropic drugs including o benzodiazepines, tranquilizer, antidepressants, anxiolytics, antiepileptics, MAO inhibitors, pimozide, lamotrigine, linezolid, intravenous methylene blue o non-benzodiazepines (exception: ≤ 10 mg zolpidem/day for not longer than 10 days during the trial) o neuroleptics (exception: ≤ 75 mg melperone/day for not longer than 10 days during the trial). However, NO exception for zolpidem and for melperone is allowed within 5 days prior to any trial visit. • Long-term prophylactic treatment (e.g. lithium, carbamazepine) • Central-acting antihypertensive medication (guanethidine, guanoxan, clonidin, prazosine, α-methyldopa, reserpine) • Digoxin • Xanthine derivatives such as Theophylline • Antiparkinson medication • Phytopharmaceuticals with anxiolytic properties (e.g. hypericum extract, valerian extract) • Muscle relaxants • Analgesics of opiate type • Anaesthetics • Barbiturates • Nootropics • Coumarin derivates • Antibiotics
- Non-medicinal psychiatric treatment during the last 2 weeks prior to baseline visit and during the course of the trial (e.g. standardised and digital psychotherapy, sleep withdrawal, phototherapy, electroconvulsive therapy, digital health applications [DiGAs]).
Trial Status by Country
| Country | Status | Start of Recruitment | Planned Patients |
|---|---|---|---|
 Austria | Recruiting | 15 Oct 2025 | 50 |
 Germany | Recruiting | 15 Oct 2025 | 450 |
Sites & Investigators
Investigational Products
Details about the medicinal products being studied in this clinical trial.
| Product Name | Role in Trial | Formulation | Administration | Max Daily Dose | Treatment Duration | EU MP Number |
|---|---|---|---|---|---|---|
Silexan 80 mg | Test | CAPSULE, SOFT | ORAL USE | 80 | 56 | PRD12518818 |
Placebo to Silexan 80 mg | Placebo | N/A | — | — | — | N/A |