Cortical ExcitabilityEarly Phase 1NCT04749745
Effects of L-theanine on Motor Cortex Excitability in Healthy Subjects: A Paired-Pulse TMS Study
A Early Phase 1 study testing L-theanine in people with Cortical Excitability and Psychiatric Disorder, run by Butler Hospital at 1 site in United States.
Trial summary
Major depressive disorder (MDD) is a serious mental illness and the leading cause of disability worldwide. New pharmacotherapeutic agents with complementary neurobiological mechanism and better side effect profile are of great needs. Read more about this study
- Who is it for?
- Ages 18 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Cortical Excitability, Psychiatric Disorder
- What is being tested?
- L-theanine
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 11 participants
- Where
- 1 siteUnited States
- Study dates
- 9 Jun 2020to 31 May 2021
- Phase
- Early Phase 1
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Adult, aged between 18 and 65 years old;
- Able to read/speak English and give informed consent
- No current or history of Axis I psychiatric disorders by DSM-5.
- Free of psychotropic medication use
Who cannot join
- History of significant acute or chronic neurological or medical disorder or condition that increases risk for seizure with TMS;
- History of alcohol use disorder, nicotine dependence, adjustment disorder;
- History of allergic reactions to L-theanine or green tea;
- Pregnancy;
- Unable/unwilling to abstain from nutraceutical supplements and psychotropic agents during participation in the study
- Unable/ unwillingness to refrain from recreational substance use (e.g. alcohol or marijuana) during participation in the study;
- Meet criteria for exclusion from TMS or MRI procedures, including intracranial metal implants or nonremovable ferromagnetic items in the head/neck.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Effects of Single-dose L-theanine on Motor Cortex Excitability in Healthy Subjects: A Double-blinded, Randomized Order, Cross-over Paired-Pulse Transcranial Magnetic Stimulation Study
Major depressive disorder (MDD) is a serious mental illness and the leading cause of disability worldwide. New pharmacotherapeutic agents with complementary neurobiological mechanism and better side effect profile are of great needs. In addition to the monoamine system, the glutamatergic system plays a crucial role in MDD.
L-theanine (N5-ethyl-L-glutamine) is the primary psychoactive component uniquely in green tea. Preclinical studies have demonstrated anti-depressant effect of L-theanine in rodents and provided evidences for its pharmacological properties of N-methyl-D-aspartate (NMDA) and gamma-aminobutyric acid (GABA) agonism. Yet these effects have not been proven in humans. Only one open-label clinical trial has studied and supported antidepressant effects of L-theanine in MDD patients. We propose using pair-pulse transcranial magnetic stimulation (ppTMS) to probe how L-theanine may manipulate the glutamatergic and GABA systems in the frontal region by changing cortical excitability first in healthy subjects. We plan to investigate the neurobiological effects of L-theanine in healthy subjects first.
Granted that the first phase pilot trial provides neurophysiological evidence of L-theanine on motor cortex excitability in human subjects, next phases of studies on L-theanine in MDD patients cortical excitability could be justified.
Read the detailed description
Background and Significance:
Major depressive disorder (MDD) is a serious mental illness and the leading cause of disability worldwide. Although many antidepressants acting on synaptic monoamine levels have been used as the first-line drug treatment for MDD, around one third of MDD are pharmacologically resistant. Side effects of these medications impose additional hardship on adherence and further affect treatment outcome. New pharmacotherapeutic agents with complementary neurobiological mechanism and better side effect profile are of great needs. In addition to the monoamine system, the glutamatergic system plays a crucial role in MDD.
L-theanine (N5-ethyl-L-glutamine) is the primary psychoactive component uniquely in green tea. Epidemiological studies support that green tea consumption is an independent factor associated with lower prevalence of depression. Preclinical studies have demonstrated anti- depressant effect of L-theanine in rodents and provided evidences for its pharmacological properties of N-methyl-D-aspartate (NMDA) and gamma-aminobutyric acid (GABA) agonism. Yet these effects have not been proven in humans. Only one open-label clinical trial has studied and supported antidepressant effects of L-theanine in MDD patients. We propose using pair-pulse transcranial magnetic stimulation (ppTMS) to probe how L-theanine may manipulate the glutamatergic and GABA systems in the frontal region by changing cortical excitability first in healthy subjects. ppTMS is a well-established technique to investigate frontal motor cortical excitability mediated by the inter-neuron NMDA and GABA receptors. Specific changes of ppTMS measures, including impaired short-term and long-term intracortical inhibition (SICI, mediated by GABA-A receptor; LICI, mediated by GABA-B receptor) and intracortical facilitation (ICF, mediated by NMDA receptor), have been demonstrated in MDD. Using this technique, we plan to investigate the neurobiological effects of L-theanine in healthy subjects first.
Granted that the first phase pilot trial provides neurophysiological evidence of L-theanine on motor cortex excitability in human subjects, next phases of studies on L-theanine in MDD patients cortical excitability could be justified. This will lay foundation for further exploration of L-theanine's potential as an augmenting agent for MDD in a placebo- controlled design.
Aims and Hypothesis:
Given the potential NMDA and GABA agonistic effects of L-theanine, we hypothesize that it increases intracortical inhibition and facilitation through enhancement of NMDA- and GABA-receptor mediated neurotransmission, in healthy subjects (N=10 to complete study).
Study Procedures:
Double-blinded, Randomized-order, Cross-over placebo-controlled to evaluate acute effect of single-dose L-theanine on motor cortex excitability by ppTMS in 10 healthy subjects.
Dose of L-theanine or placebo is 400mg. At baseline, subjects will be randomized to L- theanine or placebo group, then receive ppTMS protocol before drug administration. The ppTMS protocol is repeated after 30min of administration. Then subjects will return to clinic after 1 week free of any medications and repeat the above protocol with the second drug condition. Visual analog scale will be used to evaluate psychosomatic symptoms and wellbeing of the subjects pre- and post-each drug administration.
Data Analytic Plan:
Wilcoxon test will be used to compare the baseline-to-post-drug means of SICI, LICI and ICF measures. Prespecified covariates include age, sex, handedness, level of fatigue will be analyzed in linear regression model. The time-condition relationship with continuous dependent variables of ICI and ICF values will be evaluated by Mixed Effect Model. Two- sided P value < 0.05 is considered statistically significant.
- Conditions
- Cortical Excitability, Psychiatric Disorder
- Being tested
- L-theanine, Placebo
- Keywords
- L-theanine, Cortical Excitability, NMDA, GABA, Paired-Pulse TMS
- Medical subject headings
- Mental Disorders
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
L-theanineDrug
The subject will receive paired-pulse TMS (ppTMS) procedure before and 30min after taking the drug orally, to assess motor cortex excitability, measured by surface electromyogram (EMG). The ppTMS procedure is administered by a TMS stimulator controlled a program software named Signal. The coil of the stimulator is placed above the scalp where the stimulation would activate the left primary motor cortex region that controls the right thumb. When a pulse stimulation is delivered by the coil, the EMG over a thumb muscle (abductor pollicis brevis) will record a motor-evoked potential on the tracing. Cross-over with placebo in two separate sessions at least 72 hours apart.
PlaceboDrug
The subject will receive paired-pulse TMS (ppTMS) procedure before and 30min after taking the drug orally, to assess motor cortex excitability, measured by surface electromyogram (EMG). The ppTMS procedure is administered by a TMS stimulator controlled a program software named Signal. The coil of the stimulator is placed above the scalp where the stimulation would activate the left primary motor cortex region that controls the right thumb. When a pulse stimulation is delivered by the coil, the EMG over a thumb muscle (abductor pollicis brevis) will record a motor-evoked potential on the tracing. Cross-over with L-theanine in two separate sessions at least 72 hours apart.
| Study group | Role | What they receive |
|---|---|---|
| L-Theanine | Active comparator | Subject will receive 400mg single dose of L-theanine, by oral ingestion with water. The capsules are prepared and dispensed by hospital pharmacy, with the investigator and participant both blinded. Receives: Drug: L-theanine; Drug: Placebo |
| Placebo | Placebo comparator | Subject will receive 400mg single dose of matching Placebo, by oral ingestion with water. The capsules are prepared and dispensed by hospital pharmacy, with the investigator and participant both blinded. Receives: Drug: L-theanine; Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
The Change of Motor Cortex Excitability Measures by ppTMS
The changes of Short-interval Intracortical Inhibition (SICI), Intracortical Facilitation (ICF), and Long-interval Intracortical Inhibition (LICI) before and 30 minutes after each drug administration.
SICI, ICF and LICI are paired-pulse TMS (ppTMS)-EMG outcome measures that assess the activity of motor cortex GABA-A, NMDA and GABA-B interneurons, respectively. They are measured by the ratio between the peak-to-peak amplitude of motor-evoked potential (MEP) elicited by a testing TMS pulse (120% of the intensity of the resting motor threshold, following a conditioning pulse at different inter-stimuli interval, 2-5 milliseconds for SICI, 10-20 milliseconds for ICF, 100-200 milliseconds for LICI) and the peak-to-peak MEP amplitude elicited by a single pulse (120% of the intensity of the resting motor threshold).
The baseline-to-post-drug change of SICI, ICF and LICI elicited by L-theanine will be compared to that elicited by placebo within each subject.
Measured: Before and 30 minutes after each drug administration (no long-term follow up as this is a study on acute effect of a single-dose agent).
Secondary outcomes (1)
The Change of Visual Analog Scale (VAS)
VAS is a quick scale to assess and track how the participant subjectively feels through out each study session, e.g. anxiety, depression, excitement, etc. The score for each word ranges from "0" being the least in your life and "100" being the most in your life. It takes 3-4 minutes to complete each VAS, and there are 4 takes of VAS during each session. The outcome measure is the change of VAS throughout the 4 time points: 1) before the baseline ppTMS procedure; 2) before drug administration; 3) 30 minutes after drug administration; 4) before discharge from the session, during the session.
Measured: Throughout each session; each session lasts up to 3 hours; 2 sessions for each subject. The 2 sessions are 3-7 days apart.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Feb 2021
- Study start9 Jun 2020
- Primary completion31 May 2021
- Study completion31 May 2021
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (29)Papers the sponsor has linked to this study.
- Other trials for Cortical ExcitabilityStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Early Phase 1
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- This is a pilot study, investigating the effects of single dose L-theanine in Healthy subjects, to further assess the validity and feasibility to study this compound in patient population.
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 11 participants (actual)
Sponsor and investigators
- Lead sponsor
- Butler Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Linda Carpenter, MD, Principal investigator, Brown University-Butler Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04749745
- Sponsor's protocol ID
- 202006-003
- Status last verified
- Aug 2021
- First submitted
- 27 Jan 2021
- Last updated
- 23 Sep 2021
- Results posted
- Yes, on ClinicalTrials.gov
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No: To protect subject confidential information.
Publications
Vuong QV, Bowyer MC, Roach PD. L-Theanine: properties, synthesis and isolation from tea. J Sci Food Agric. 2011 Aug 30;91(11):1931-9. doi: 10.1002/jsfa.4373. Epub 2011 Mar 29.
PubMed 21735448Kim J, Kim J. Green Tea, Coffee, and Caffeine Consumption Are Inversely Associated with Self-Report Lifetime Depression in the Korean Population. Nutrients. 2018 Sep 1;10(9):1201. doi: 10.3390/nu10091201.
PubMed 30200434Hintikka J, Tolmunen T, Honkalampi K, Haatainen K, Koivumaa-Honkanen H, Tanskanen A, Viinamaki H. Daily tea drinking is associated with a low level of depressive symptoms in the Finnish general population. Eur J Epidemiol. 2005;20(4):359-63. doi: 10.1007/s10654-005-0148-2.
PubMed 15971509Hozawa A, Kuriyama S, Nakaya N, Ohmori-Matsuda K, Kakizaki M, Sone T, Nagai M, Sugawara Y, Nitta A, Tomata Y, Niu K, Tsuji I. Green tea consumption is associated with lower psychological distress in a general population: the Ohsaki Cohort 2006 Study. Am J Clin Nutr. 2009 Nov;90(5):1390-6. doi: 10.3945/ajcn.2009.28214. Epub 2009 Sep 30.
PubMed 19793850Wakabayashi C, Numakawa T, Ninomiya M, Chiba S, Kunugi H. Behavioral and molecular evidence for psychotropic effects in L-theanine. Psychopharmacology (Berl). 2012 Feb;219(4):1099-109. doi: 10.1007/s00213-011-2440-z. Epub 2011 Aug 23.
PubMed 21861094Egashira N, Ishigami N, Pu F, Mishima K, Iwasaki K, Orito K, Oishi R, Fujiwara M. Theanine prevents memory impairment induced by repeated cerebral ischemia in rats. Phytother Res. 2008 Jan;22(1):65-8. doi: 10.1002/ptr.2261.
PubMed 17705146Lardner AL. Neurobiological effects of the green tea constituent theanine and its potential role in the treatment of psychiatric and neurodegenerative disorders. Nutr Neurosci. 2014 Jul;17(4):145-55. doi: 10.1179/1476830513Y.0000000079. Epub 2013 Nov 26.
PubMed 23883567Hidese S, Ota M, Wakabayashi C, Noda T, Ozawa H, Okubo T, Kunugi H. Effects of chronic l-theanine administration in patients with major depressive disorder: an open-label study. Acta Neuropsychiatr. 2017 Apr;29(2):72-79. doi: 10.1017/neu.2016.33. Epub 2016 Jul 11.
PubMed 27396868Paulus W, Classen J, Cohen LG, Large CH, Di Lazzaro V, Nitsche M, Pascual-Leone A, Rosenow F, Rothwell JC, Ziemann U. State of the art: Pharmacologic effects on cortical excitability measures tested by transcranial magnetic stimulation. Brain Stimul. 2008 Jul;1(3):151-63. doi: 10.1016/j.brs.2008.06.002. Epub 2008 Jun 30.
PubMed 20633382Radhu N, de Jesus DR, Ravindran LN, Zanjani A, Fitzgerald PB, Daskalakis ZJ. A meta-analysis of cortical inhibition and excitability using transcranial magnetic stimulation in psychiatric disorders. Clin Neurophysiol. 2013 Jul;124(7):1309-20. doi: 10.1016/j.clinph.2013.01.014. Epub 2013 Feb 26.
PubMed 23485366Bajbouj M, Lisanby SH, Lang UE, Danker-Hopfe H, Heuser I, Neu P. Evidence for impaired cortical inhibition in patients with unipolar major depression. Biol Psychiatry. 2006 Mar 1;59(5):395-400. doi: 10.1016/j.biopsych.2005.07.036. Epub 2005 Sep 28.
PubMed 16197927Lefaucheur JP, Lucas B, Andraud F, Hogrel JY, Bellivier F, Del Cul A, Rousseva A, Leboyer M, Paillere-Martinot ML. Inter-hemispheric asymmetry of motor corticospinal excitability in major depression studied by transcranial magnetic stimulation. J Psychiatr Res. 2008 Apr;42(5):389-98. doi: 10.1016/j.jpsychires.2007.03.001. Epub 2007 Apr 20.
PubMed 17449060Levinson AJ, Fitzgerald PB, Favalli G, Blumberger DM, Daigle M, Daskalakis ZJ. Evidence of cortical inhibitory deficits in major depressive disorder. Biol Psychiatry. 2010 Mar 1;67(5):458-64. doi: 10.1016/j.biopsych.2009.09.025. Epub 2009 Nov 17.
PubMed 19922906Jeng JS, Li CT, Lin HC, Tsai SJ, Bai YM, Su TP, Chang YW, Cheng CM. Antidepressant-resistant depression is characterized by reduced short- and long-interval cortical inhibition. Psychol Med. 2020 Jun;50(8):1285-1291. doi: 10.1017/S0033291719001223. Epub 2019 Jun 3.
PubMed 31155020Ziemann U, Chen R, Cohen LG, Hallett M. Dextromethorphan decreases the excitability of the human motor cortex. Neurology. 1998 Nov;51(5):1320-4. doi: 10.1212/wnl.51.5.1320.
PubMed 9818853
Study at a glance
From the registry record, last updated by the sponsor on 23 Sep 2021. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Single-dose L-theanine on Motor Cortex Excitability in Healthy Subjects: A Double-blinded, Randomized Order, Cross-over Paired-Pulse Transcranial Magnetic Stimulation Study
- ClinicalTrials.gov ID
- NCT04749745
- Acronym / sponsor ID
- 202006-003
- Conditions
- Cortical Excitability, Psychiatric Disorder
- Keywords
- L-theanine, Cortical Excitability, NMDA, GABA, Paired-Pulse TMS
- Phase
- Early Phase 1
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 11 participants (actual)
- Lead sponsor
- Butler HospitalUniversity, hospital or other
- Study start
- 9 Jun 2020 (actual)
- Primary completion
- 31 May 2021 (actual)
- Study completion
- 31 May 2021 (actual)
- First posted
- 11 Feb 2021 (actual)
- Results
- Posted 23 Sep 2021
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Major depressive disorder (MDD) is a serious mental illness and the leading cause of disability worldwide. New pharmacotherapeutic agents with complementary neurobiological mechanism and better side effect profile are of great needs. In addition to the monoamine system, the glutamatergic system plays a crucial role in MDD.
L-theanine (N5-ethyl-L-glutamine) is the primary psychoactive component uniquely in green tea. Preclinical studies have demonstrated anti-depressant effect of L-theanine in rodents and provided evidences for its pharmacological properties of N-methyl-D-aspartate (NMDA) and gamma-aminobutyric acid (GABA) agonism. Yet these effects have not been proven in humans. Only one open-label clinical trial has studied and supported antidepressant effects of L-theanine in MDD patients. We propose using pair-pulse transcranial magnetic stimulation (ppTMS) to probe how L-theanine may manipulate the glutamatergic and GABA systems in the frontal region by changing cortical excitability first in healthy subjects. We plan to investigate the neurobiological effects of L-theanine in healthy subjects first.
Granted that the first phase pilot trial provides neurophysiological evidence of L-theanine on motor cortex excitability in human subjects, next phases of studies on L-theanine in MDD patients cortical excitability could be justified.
Detailed description
Background and Significance:
Major depressive disorder (MDD) is a serious mental illness and the leading cause of disability worldwide. Although many antidepressants acting on synaptic monoamine levels have been used as the first-line drug treatment for MDD, around one third of MDD are pharmacologically resistant. Side effects of these medications impose additional hardship on adherence and further affect treatment outcome. New pharmacotherapeutic agents with complementary neurobiological mechanism and better side effect profile are of great needs. In addition to the monoamine system, the glutamatergic system plays a crucial role in MDD.
L-theanine (N5-ethyl-L-glutamine) is the primary psychoactive component uniquely in green tea. Epidemiological studies support that green tea consumption is an independent factor associated with lower prevalence of depression. Preclinical studies have demonstrated anti- depressant effect of L-theanine in rodents and provided evidences for its pharmacological properties of N-methyl-D-aspartate (NMDA) and gamma-aminobutyric acid (GABA) agonism. Yet these effects have not been proven in humans. Only one open-label clinical trial has studied and supported antidepressant effects of L-theanine in MDD patients. We propose using pair-pulse transcranial magnetic stimulation (ppTMS) to probe how L-theanine may manipulate the glutamatergic and GABA systems in the frontal region by changing cortical excitability first in healthy subjects. ppTMS is a well-established technique to investigate frontal motor cortical excitability mediated by the inter-neuron NMDA and GABA receptors. Specific changes of ppTMS measures, including impaired short-term and long-term intracortical inhibition (SICI, mediated by GABA-A receptor; LICI, mediated by GABA-B receptor) and intracortical facilitation (ICF, mediated by NMDA receptor), have been demonstrated in MDD. Using this technique, we plan to investigate the neurobiological effects of L-theanine in healthy subjects first.
Granted that the first phase pilot trial provides neurophysiological evidence of L-theanine on motor cortex excitability in human subjects, next phases of studies on L-theanine in MDD patients cortical excitability could be justified. This will lay foundation for further exploration of L-theanine's potential as an augmenting agent for MDD in a placebo- controlled design.
Aims and Hypothesis:
Given the potential NMDA and GABA agonistic effects of L-theanine, we hypothesize that it increases intracortical inhibition and facilitation through enhancement of NMDA- and GABA-receptor mediated neurotransmission, in healthy subjects (N=10 to complete study).
Study Procedures:
Double-blinded, Randomized-order, Cross-over placebo-controlled to evaluate acute effect of single-dose L-theanine on motor cortex excitability by ppTMS in 10 healthy subjects.
Dose of L-theanine or placebo is 400mg. At baseline, subjects will be randomized to L- theanine or placebo group, then receive ppTMS protocol before drug administration. The ppTMS protocol is repeated after 30min of administration. Then subjects will return to clinic after 1 week free of any medications and repeat the above protocol with the second drug condition. Visual analog scale will be used to evaluate psychosomatic symptoms and wellbeing of the subjects pre- and post-each drug administration.
Data Analytic Plan:
Wilcoxon test will be used to compare the baseline-to-post-drug means of SICI, LICI and ICF measures. Prespecified covariates include age, sex, handedness, level of fatigue will be analyzed in linear regression model. The time-condition relationship with continuous dependent variables of ICI and ICF values will be evaluated by Mixed Effect Model. Two- sided P value < 0.05 is considered statistically significant.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
- Model description
- This is a pilot study, investigating the effects of single dose L-theanine in Healthy subjects, to further assess the validity and feasibility to study this compound in patient population.
| Arm | Type | Receives |
|---|---|---|
| L-Theanine | Active comparator | Drug: L-theanine, Drug: PlaceboSubject will receive 400mg single dose of L-theanine, by oral ingestion with water. The capsules are prepared and dispensed by hospital pharmacy, with the investigator and participant both blinded. |
| Placebo | Placebo comparator | Drug: L-theanine, Drug: PlaceboSubject will receive 400mg single dose of matching Placebo, by oral ingestion with water. The capsules are prepared and dispensed by hospital pharmacy, with the investigator and participant both blinded. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Adult, aged between 18 and 65 years old;
- Able to read/speak English and give informed consent
- No current or history of Axis I psychiatric disorders by DSM-5.
- Free of psychotropic medication use
Key exclusion criteria (7 listed)
- History of significant acute or chronic neurological or medical disorder or condition that increases risk for seizure with TMS;
- History of alcohol use disorder, nicotine dependence, adjustment disorder;
- History of allergic reactions to L-theanine or green tea;
- Pregnancy;
- Unable/unwilling to abstain from nutraceutical supplements and psychotropic agents during participation in the study
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| L-theanineThe subject will receive paired-pulse TMS (ppTMS) procedure before and 30min after taking the drug orally, to assess motor cortex excitability, measured by surface electromyogram (EMG). The ppTMS procedure is administered by a TMS stimulator controlled a program software named Signal. The coil of the stimulator is placed above the scalp where the stimulation would activate the left primary motor cortex region that controls the right thumb. When a pulse stimulation is delivered by the coil, the EMG over a thumb muscle (abductor pollicis brevis) will record a motor-evoked potential on the tracing. Cross-over with placebo in two separate sessions at least 72 hours apart. | Drug | L-Theanine, Placebo |
| PlaceboThe subject will receive paired-pulse TMS (ppTMS) procedure before and 30min after taking the drug orally, to assess motor cortex excitability, measured by surface electromyogram (EMG). The ppTMS procedure is administered by a TMS stimulator controlled a program software named Signal. The coil of the stimulator is placed above the scalp where the stimulation would activate the left primary motor cortex region that controls the right thumb. When a pulse stimulation is delivered by the coil, the EMG over a thumb muscle (abductor pollicis brevis) will record a motor-evoked potential on the tracing. Cross-over with L-theanine in two separate sessions at least 72 hours apart. | Drug | L-Theanine, Placebo |
Primary outcome
The Change of Motor Cortex Excitability Measures by ppTMS
Time frame: Before and 30 minutes after each drug administration (no long-term follow up as this is a study on acute effect of a single-dose agent).
The changes of Short-interval Intracortical Inhibition (SICI), Intracortical Facilitation (ICF), and Long-interval Intracortical Inhibition (LICI) before and 30 minutes after each drug administration. SICI, ICF and LICI are paired-pulse TMS (ppTMS)-EMG outcome measures that assess the activity of motor cortex GABA-A, NMDA and GABA-B interneurons, respectively. They are measured by the ratio between the peak-to-peak amplitude of motor-evoked potential (MEP) elicited by a testing TMS pulse (120% of the intensity of the resting motor threshold, following a conditioning pulse at different inter-stimuli interval, 2-5 milliseconds for SICI, 10-20 milliseconds for ICF, 100-200 milliseconds for LICI) and the peak-to-peak MEP amplitude elicited by a single pulse (120% of the intensity of the resting motor threshold). The baseline-to-post-drug change of SICI, ICF and LICI elicited by L-theanine will be compared to that elicited by placebo within each subject.
1 secondary outcome
The Change of Visual Analog Scale (VAS)
Time frame: Throughout each session; each session lasts up to 3 hours; 2 sessions for each subject. The 2 sessions are 3-7 days apart.
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Sep 2021.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Background: PubMed 21735448Vuong QV, Bowyer MC, Roach PD. L-Theanine: properties, synthesis and isolation from tea. J Sci Food Agric. 2011 Aug 30;91(11):1931-9. doi: 10.1002/jsfa.4373. Epub 2011 Mar 29.
- Background: PubMed 30200434Kim J, Kim J. Green Tea, Coffee, and Caffeine Consumption Are Inversely Associated with Self-Report Lifetime Depression in the Korean Population. Nutrients. 2018 Sep 1;10(9):1201. doi: 10.3390/nu10091201.
- Background: PubMed 15971509Hintikka J, Tolmunen T, Honkalampi K, Haatainen K, Koivumaa-Honkanen H, Tanskanen A, Viinamaki H. Daily tea drinking is associated with a low level of depressive symptoms in the Finnish general population. Eur J Epidemiol. 2005;20(4):359-63. doi: 10.1007/s10654-005-0148-2.
- Background: PubMed 19793850Hozawa A, Kuriyama S, Nakaya N, Ohmori-Matsuda K, Kakizaki M, Sone T, Nagai M, Sugawara Y, Nitta A, Tomata Y, Niu K, Tsuji I. Green tea consumption is associated with lower psychological distress in a general population: the Ohsaki Cohort 2006 Study. Am J Clin Nutr. 2009 Nov;90(5):1390-6. doi: 10.3945/ajcn.2009.28214. Epub 2009 Sep 30.
- Background: PubMed 21861094Wakabayashi C, Numakawa T, Ninomiya M, Chiba S, Kunugi H. Behavioral and molecular evidence for psychotropic effects in L-theanine. Psychopharmacology (Berl). 2012 Feb;219(4):1099-109. doi: 10.1007/s00213-011-2440-z. Epub 2011 Aug 23.
- Background: PubMed 17705146Egashira N, Ishigami N, Pu F, Mishima K, Iwasaki K, Orito K, Oishi R, Fujiwara M. Theanine prevents memory impairment induced by repeated cerebral ischemia in rats. Phytother Res. 2008 Jan;22(1):65-8. doi: 10.1002/ptr.2261.
- Background: PubMed 23883567Lardner AL. Neurobiological effects of the green tea constituent theanine and its potential role in the treatment of psychiatric and neurodegenerative disorders. Nutr Neurosci. 2014 Jul;17(4):145-55. doi: 10.1179/1476830513Y.0000000079. Epub 2013 Nov 26.
- Background: PubMed 27396868Hidese S, Ota M, Wakabayashi C, Noda T, Ozawa H, Okubo T, Kunugi H. Effects of chronic l-theanine administration in patients with major depressive disorder: an open-label study. Acta Neuropsychiatr. 2017 Apr;29(2):72-79. doi: 10.1017/neu.2016.33. Epub 2016 Jul 11.
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- Individual participant dataSharing planned: No. To protect subject confidential information.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Linda Carpenter, MD principal investigator
Brown University-Butler Hospital
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Early Phase 1 study testing L-theanine in people with Cortical Excitability and Psychiatric Disorder, run by Butler Hospital at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 23 Sep 2021. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Early Phase 1 (sometimes called Phase 0) studies give a very small amount of a treatment to a few people, mainly to see how the body handles it.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 23 Sep 2021). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
The Change of Motor Cortex Excitability Measures by ppTMS (time frame: Before and 30 minutes after each drug administration (no long-term follow up as this is a study on acute effect of a single-dose agent).). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT04749745, which also lists 29 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 23 Sep 2021.