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L-Theanine in the Management of Schizophrenia

This study has been completed.
Stanley Medical Research Institute
Beersheva Mental Health Center
Information provided by:
Sha’ar Menashe Mental Health Center Identifier:
First received: September 5, 2006
Last updated: December 15, 2008
Last verified: December 2008
The aim of the proposed study is to investigate the efficacy and safety of add-on gamma-glutamylethylamide (L-theanine) versus a placebo for antipsychotic treatment for 8 weeks in a randomized, double-blind, parallel group study of 60 patients with schizophrenia and schizoaffective disorders.

Condition Intervention Phase
Dietary Supplement: L-Theanine
Other: Placebo
Phase 3

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Participant, Investigator)
Primary Purpose: Treatment
Official Title: The Value of Augmenting L-Theanine in the Management of Schizophrenia: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Resource links provided by NLM:

Further study details as provided by Sha’ar Menashe Mental Health Center:

Primary Outcome Measures:
  • The Clinical Global Impression Scale [ Time Frame: every two weeks ]
  • The Positive and Negative Syndrome Scale [ Time Frame: every two weeks ]
  • The Scale for the Assessment of Negative Symptoms [ Time Frame: every two weeks ]
  • The Calgary Depression Scale for Schizophrenia [ Time Frame: every two weeks ]
  • The Hamilton Scale for Anxiety [ Time Frame: every two weeks ]
  • Cambridge Neuropsychological Test Automated Battery (CANTAB) [ Time Frame: every 4 weeks ]

Secondary Outcome Measures:
  • The Global Assessment of Functioning [ Time Frame: every two weeks ]
  • The Talbieh Brief Distress Inventory [ Time Frame: every two weeks ]
  • The State/Trait Anxiety Inventory [ Time Frame: every two weeks ]
  • The Quality of Life Scale [ Time Frame: every two weeks ]
  • The Quality of Life Enjoyment and Satisfaction Questionnaire [ Time Frame: every two weeks ]
  • The Extrapyramidal Symptom Rating Scale [ Time Frame: every two weeks ]
  • Barnes Akathisia Scale [ Time Frame: every two weeks ]

Enrollment: 60
Study Start Date: October 2006
Study Completion Date: December 2008
Primary Completion Date: December 2008 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: L-Theanine Dietary Supplement: L-Theanine
400 mg/day, caps.
Placebo Comparator: Placebo Other: Placebo

Detailed Description:

This is a two-year randomized placebo-controlled double-blind investigation of the use of augmentative L-theanine in the management of 60 patients with schizophrenia and schizoaffective disorders. We will investigate several outcome variables in these patients including the positive and negative symptoms, affective features, emotional distress, neuropsychological testing, side effects, and the quality of life. Participating subjects on stable antipsychotic treatment will be randomized to receive for 8 weeks either L-theanine (400 mg/day) or a placebo in addition to regular ongoing antipsychotic medication for 8 weeks. Subjects will be assessed at baseline and after 2, 4, 6, and 8 weeks of treatment using psychiatric rating scales, self-reported questionnaires, and a neuropsychological battery of tests. The efficacy and safety of augmenting antipsychotic treatment with L-theanine will be analyzed.

The Cambridge Neuropsychological Test Automated Battery (CANTAB) will be administered at commencement and completion of the study. The CANTAB battery consists of a series of interrelated computerized tests of visual and movement skills, attention and memory, and executive function, administered via a touch sensitive screen. The nonverbal nature of the CANTAB tests makes them largely language independent and culture free. These tests are run on an IBM-compatible personal computer with a touch-sensitive screen. Neuropsychological testing lasts approximately 2 hours. Subjects complete the tests in a fixed order with a break half-way through the testing session. For a description of the nature of these tests, the performance measures used, and how the test scores are derived, see ( The neuropsychological tests are categorized onto five cognitive domains: visual and movement skills, attention, memory, learning, sustained attention, and executive function: Motor Screening, Big/Little Circle, Reaction Time, Matching to Sample Visual Search, Delayed Matching to Sample, Pattern Recognition Memory, Spatial Recognition Memory, Spatial Span, Rapid visual information processing, Spatial working memory, Intra/Extra Dimensional Set Shift, and Stockings of Cambridge. In addition to raw scores from these tasks, the average value of the z-scores of the CANTAB neurocognitive tasks will be used to determine cognitive indices in specific domains.


Ages Eligible for Study:   18 Years to 60 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Age 18-60 years, men or women
  • DSM-IV criteria for schizophrenia or schizoaffective disorder
  • At least 4 on the Clinical Global Impression Scale
  • At least two weeks of ongoing treatment with current antipsychotic agents.
  • Ability and willingness to sign an informed consent form for participation in the study.

Exclusion Criteria:

  • Evidence of serious neurologic or endocrine disorder, for example severe head trauma, seizure disorder, dementia, Cushings disease, or thyroid disorder, mental retardation, alcohol or drug abuse.
  • Renal disease
  • Hepatic dysfunction
  • Pregnant women
  • Patients receiving mood stabilizing medications.
  Contacts and Locations
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Please refer to this study by its identifier: NCT00372151

Be'er Sheva Mental Health Center
Be'er Sheva, Israel
Sha'ar Menashe Mental Health Center
Hadera, Israel, 38814
Sponsors and Collaborators
Sha’ar Menashe Mental Health Center
Stanley Medical Research Institute
Beersheva Mental Health Center
Principal Investigator: Michael S Ritsner, MD, PhD Sha’ar Menashe Mental Health Center
Study Director: Yael Ratner, MD Sha’ar Menashe Mental Health Center
Study Director: Anatoly Gibel, MD Sha’ar Menashe Mental Health Center
Study Director: Chanoch Miodownik, MD Be'er Sheva Mental Health Center
Study Director: Tatyana Shleifer, MD Be'er Sheva Mental Health Center
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Michael S Ritsner, Technion Identifier: NCT00372151     History of Changes
Other Study ID Numbers: Theanine 10/2006.ctil
Study First Received: September 5, 2006
Last Updated: December 15, 2008

Keywords provided by Sha’ar Menashe Mental Health Center:
Schizoaffective disorders

Additional relevant MeSH terms:
Schizophrenia Spectrum and Other Psychotic Disorders
Mental Disorders processed this record on April 28, 2017