None listed
Conditions
Brief summary
The objective of this trial is to assess the effectiveness and safety of L-theanine (an amino acid constituent of green tea [Camellia sinensis]) as an adjunctive therapy to treat GAD by conducting a phase II double-blind randomised controlled trial. It is hypothesised that L-theanine will be superior to placebo in reducing anxiety in participants with GAD.
Interventions
L-theanine capsules (each capsule contains 225mg of L-theanine and 25mg excipients).
One capsule will be taken orally twice per day (totaling 450mg L-theanine OR placebo) for the first four weeks of the the trial. In cases of non-response (determined by reduction in SIGH-A score <35% from baseline), the dose will be doubled (2 capsules twice per day; equating to 900mg L-theanine OR placebo) from week-4 onwards.
All participants will receive placebo capsules (microcellulose) in a single blind
L-theanine capsules (each capsule contains 225mg of L-theanine and 25mg excipients). One capsule will be taken orally twice per day (totaling 450mg L-theanine OR placebo) for the first four weeks of the the trial. In cases of non-response (determined by reduction in SIGH-A score <35% from baseline), the dose will be doubled (2 capsules twice per day; equating to 900mg L-theanine OR placebo) from week-4 onwards. All participants will receive placebo capsules (microcellulose) in a single blinded manner for the final 2-weeks of the trial (placebo run-out from week-8 to week-10). Participants will be required to take the capsules as instructed during the 10 weeks of the study. At each follow-up visit, the participants will be asked to return their current treatment container with any remaining capsules inside. These will be counted and recorded to determine participant compliance to the treatment regime.
Sponsors
Dr. Jerome Sarris
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Treatment
Masking
Blinded (masking used) (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
All
Age
18 Years to 70 Years
Healthy volunteers
No
Inclusion criteria
1. Aged between 18-70 years 2. Meets the DSM-IV and DSM-5 diagnostic criteria for generalised anxiety disorder (GAD) based on structured interview (Mini International Neuropsychiatric Interview- 6.0 [MINI 6.0]. Note that while the MINI 6.0 uses the DSM-IV criteria, the same criteria are used in the DSM-5) 3. Currently taking an antidepressant for anxiety 4. Presents with anxiety (SIGH-A score equal to or greater than 16) at the time of study entry 5. Fluent in spoken and written English
Exclusion criteria
1. Primary diagnosis other than GAD 2. Presentation of moderate to severe depressive symptoms (SIGMA score equal to or greater than 16) at time of study entry 3. Presentation of suicidal ideation (score of 3 or greater on SIGMA suicidal thoughts domain) at time of study entry 4. Current diagnosis of a psychotic disorder (bipolar disorder I, schizophrenia) or Major Depressive Disorder (current episode) on structured interview (MINI 6.0) 5. Current substance/alcohol use disorder on structured interview (MINI 6.0) 6. Three or more failed trials of antidepressant pharmacotherapy for the current GAD episode. A failed trial is defined as limited improvement (equal to or less than 50% improvement) in symptoms after trialing an antidepressant for an adequate dose and duration (recommended therapeutic dose for at least 4 weeks). 7. Drinking more than 3 cups of tea (in any form e.g. black or green) per day 8. Recently commenced psychotherapy (within four weeks of study entry) 9. Known or suspected clinically unstable systemic medical disorder (e.g. cancer, organ failure) or at the discretion of the medical investigators. 10. Pregnancy or breastfeeding, or trying to conceive 11. Not using a medically approved form of contraception (including abstinence) if female and of childbearing age 12. Unable to participate in all scheduled visits, treatment plan, tests and other trial procedures according to the protocol
Outcome results
None listed