Theanine in the Adjunctive Treatment of Generalised Anxiety Disorder: A Double-Blind Randomised Placebo-Controlled Trial

Phase 2

Completed

• Conditions: Generalized Anxiety Disorder; Mental Health - Anxiety

• Registration Number: ACTRN12616000759493
• Lead Sponsor: Dr. Jerome Sarris

Brief Summary

Partial or non-response to antidepressants in Generalized Anxiety Disorder (GAD) is common in clinical settings, and adjunctive biological interventions may be required. Adjunctive herbal and nutraceutical treatments are a novel and promising treatment option. L-theanine is a non-protein amino acid derived most-commonly from tea (Camellia sinensis) leaves, which may be beneficial in the treatment of anxiety and sleep disturbance as suggested by preliminary evidence. We conducted a 10-week study (consisting of an 8-week double-blind placebo-controlled controlled period, and 1-week pre-study and 2-week post-study single-blinded observational periods) involving 46 participants with a DSM-5 diagnosis of GAD. Participants received adjunctive L-theanine (450-900mg) or matching placebo with their current stable antidepressant treatment, and were assessed on anxiety, sleep quality, and cognition outcomes. Results revealed that adjunctive L-theanine did not outperform placebo for anxiety reduction on the HAMA (p = 0.73) nor insomnia severity on the Insomnia Severity Index (ISI; p = 0.35). However, LT treated participants reported greater self-reported sleep satisfaction than placebo (ISI item 4; p = 0.015). Further, a separation in favour of L-theanine was noted on the ISI in those with non-clinical levels of insomnia symptoms (ISI = 14; p = 0.007). No significant cognitive effects (trail making time and the modified emotional Stroop) were revealed.

Detailed Description

Not available

Study Timeline

• Results First Posted: 1900-01-01
• Study Start: 2016-06-09
• Study Completion: 2018-06-14
• Last Update Posted: 13 January 2020

Recruitment & Eligibility

• Status: Completed
• Sex: All
• Target Recruitment: 47

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

Study & Design

• Study Type: Interventional
• Study Design: Not specified