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| Name | Class |
|---|---|
| Texas Tech University Health Sciences Center | OTHER |
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L-theanine and caffeine are two natural constituents of tea. Both of these compounds are among the U.S. Food and Drug Administration's list of Generally Recognized as Safe (GRAS) substances. Results of several clinical trials the PI and his team has conducted are consistent with results of many others to indicate that oral intake of each of 2.5 mg/kg body weight of L-theanine and 2.0 mg/kg body weight of caffeine is associated with improved attention in adults. Furthermore, there is evidence to suggest that, when taken in combination, L-theanine and caffeine seem to have additive effects in improving attention in adults. However, the specific actions of these substances have not been examined in children and adolescents with attention deficit hyperactivity disorder (ADHD), who are characterized by impaired attention, hyperkinesia and impulsivity.
Therefore, the investigators plan to study the functional activity of brains (both at rest and when performing standard tasks designed to measure attention) in children diagnosed with ADHD using functional magnetic resonance imaging, after they consume either 2.5 mg/kg of L-theanine, 2.0 mg/kg of caffeine and their combination as compared to a placebo (water). Based on our previous findings, the investigators expect to observe improvements (speed of responding and accuracy) in standard tests of attention with intake of L-theanine, caffeine and their combination as compared to the placebo. The investigators also expect to observe decreased functional activity in brain regions that typically show increased activity during mind wandering with intake of L-theanine, caffeine and their combination.
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| L-theanine | Dietary Supplement | Oral administration of 2.5 mg/kg body weight of L-theanine dissolved in 100 ml of water | ||
| Caffeine | Dietary Supplement | Oral administration of 2.0 mg/kg body weight of caffeine dissolved in 100 ml of water | ||
| L-theanine-Caffeine Combination | Dietary Supplement | Oral administration of a combination of 2.5 mg/kg body weight of L-theanine and 2.0 mg/kg body weight of caffeine dissolved in 100 ml of water | ||
| Placebo | Other | Oral administration of 100 ml of water |
| Measure | Description | Time Frame |
|---|---|---|
| Differences of fMRI blood oxygen level dependent (BOLD) responses of the brain in response to Stop Signals of an SSRT recorded following administration of each treatment and the placebo | L-theanine, caffeine, L-theanine-caffeine combination and placebo will be administered on 4 separate days (at least 5 days apart) in a random counter-balanced order. Differences of functional magnetic resonance imaging reactivity of the whole brain, anterior and posterior nodes of the default mode network, bilateral dorsolateral prefrontal cortex and anterior cingulate cortex in response to stop signals of a stop signal reaction time task following administration of each treatment will be compared with the placebo. | 45 minutes after the administration of each treatment / placebo |
| Differences of fMRI blood oxygen level dependent (BOLD) responses of the brain in a Go-NoGo CPT recorded following administration of each treatment and the placebo | L-theanine, caffeine, L-theanine-caffeine combination and placebo will be administered on 4 separate days (at least 5 days apart) in a random counter-balanced order. Differences of functional magnetic resonance imaging reactivity of the whole brain, anterior and posterior nodes of the default mode network, bilateral dorsolateral prefrontal cortex and anterior cingulate cortex in Go-NoGo continuous performance task following administration of each treatment will be compared with the placebo. | 60 minutes after the administration of each treatment / placebo |
| Differences of resting state fMRI functional connectivity recorded following administration of each treatment and the placebo | L-theanine, caffeine, L-theanine-caffeine combination and placebo will be administered on 4 separate days (at least 5 days apart) in a random counter-balanced order. Differences of functional magnetic resonance imaging resting state functional connectivity of the anterior and posterior nodes of the default mode network, bilateral dorsolateral prefrontal cortex and anterior cingulate cortex and the remaining regions of the brain following administration of each treatment will be compared with the placebo. | 75 minutes after the administration of each treatment / placebo |
| Measure | Description | Time Frame |
|---|---|---|
| Differences of cerebral blood flow measured following administration of each treatment and the placebo | L-theanine, caffeine, L-theanine-caffeine combination and placebo will be administered on 4 separate days (at least 5 days apart) in a random counter-balanced order. Differences of cerebral blood flow estimated using arterial spin labeled echo following administration of each treatment will be compared with the placebo. |
| Measure | Description | Time Frame |
|---|---|---|
| Differences of commission errors in SSRT following administration of each treatment and the placebo | L-theanine, caffeine, L-theanine-caffeine combination and placebo will be administered on 4 separate days (at least 5 days apart) in a random counter-balanced order. Differences of commission errors of the stop signal reaction time task performed in the magnetic resonance imaging scanner following administration of each treatment will be compared with the placebo. |
Inclusion Criteria:
Exclusion Criteria:
Participant eligibility is based on self-representation of gender identity
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| Name | Affiliation | Role |
|---|---|---|
| Chanaka Kahathuduwa, MBBS PhD | Texas Tech University | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Texas Tech University - Department of Human Development and Family Studies | Lubbock | Texas | 79409 | United States |
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2.5 mg/kg body weight of L-theanine, 2.0 mg/kg body weight of caffeine and their combination each dissolved in 100 ml of water (solvent) or the solvent alone (i.e. placebo) will be administered on 4 separate days (at least 5 days apart) in a random counter-balanced order.
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| 80 minutes following administration of each treatment / placebo |
| Differences of delay discounting following administration of each treatment and the placebo | L-theanine, caffeine, L-theanine-caffeine combination and placebo will be administered on 4 separate days (at least 5 days apart) in a random counter-balanced order. Differences of delay discounting as measured using a delay discounting task presented on a laptop computer following administration of each treatment will be compared with the placebo. | 140 minutes following administration of each treatment / placebo |
| Differences of stop signal delay following administration of each treatment and the placebo | L-theanine, caffeine, L-theanine-caffeine combination and placebo will be administered on 4 separate days (at least 5 days apart) in a random counter-balanced order. Differences of stop signal delay of a stop signal reaction time task performed in the magnetic resonance imaging scanner following administration of each treatment will be compared with the placebo. | 45 minutes following administration of each treatment / placebo |
| Differences of reaction times of correct Go responses in a Go-NoGo CPT following administration of each treatment and the placebo | L-theanine, caffeine, L-theanine-caffeine combination and placebo will be administered on 4 separate days (at least 5 days apart) in a random counter-balanced order. Differences of reaction times of correct Go responses in a Go-NoGo continuous performance task performed in the magnetic resonance imaging scanner following administration of each treatment will be compared with the placebo. | 60 minutes following administration of each treatment / placebo |
| Differences of commission errors in the Go-NoGo CPT following administration of each treatment and the placebo | L-theanine, caffeine, L-theanine-caffeine combination and placebo will be administered on 4 separate days (at least 5 days apart) in a random counter-balanced order. Differences of commission errors in the Go-NoGo continuous performance task performed in the magnetic resonance imaging scanner following administration of each treatment will be compared with the placebo. | 60 minutes following administration of each treatment / placebo |
| Differences of performance in Flanker Inhibitory Control and Attention Test following administration of each treatment and the placebo | L-theanine, caffeine, L-theanine-caffeine combination and placebo will be administered on 4 separate days (at least 5 days apart) in a random counter-balanced order. Differences of performance in Flanker Inhibitory Control and Attention Test of the NIH Toolbox Cognition Battery following administration of each treatment will be compared with the placebo. | 100 minutes following administration of each treatment / placebo |
| Differences of performance in Dimensional Change Card Sort Test following administration of each treatment and the placebo | L-theanine, caffeine, L-theanine-caffeine combination and placebo will be administered on 4 separate days (at least 5 days apart) in a random counter-balanced order. Differences of performance in Dimensional Change Card Sort Test of the NIH Toolbox Cognition Battery following administration of each treatment will be compared with the placebo. | 100 minutes following administration of each treatment / placebo |
| Differences of performance in Pattern Comparison Processing Speed Test following administration of each treatment and the placebo | L-theanine, caffeine, L-theanine-caffeine combination and placebo will be administered on 4 separate days (at least 5 days apart) in a random counter-balanced order. Differences of performance in Pattern Comparison Processing Speed Test of the NIH Toolbox Cognition Battery following administration of each treatment will be compared with the placebo. | 100 minutes following administration of each treatment / placebo |
| Differences of post- vs. pre-treatment change of STAI-CH State Scale following administration of each treatment and the placebo | L-theanine, caffeine, L-theanine-caffeine combination and placebo will be administered on 4 separate days (at least 5 days apart) in a random counter-balanced order. Differences of State Trait Anxiety Inventory for Children (State Questionnaire) immediately prior to and following administration of each treatment will be compared with the corresponding post- vs. pre-treatment change of placebo. | Immediately before and 90 minutes after administration of each treatment / placebo |
| 45 minutes following administration of each treatment / placebo |
| Differences of omission errors in SSRT following administration of each treatment and the placebo | L-theanine, caffeine, L-theanine-caffeine combination and placebo will be administered on 4 separate days (at least 5 days apart) in a random counter-balanced order. Differences of omission errors of the stop signal reaction time task performed in the magnetic resonance imaging scanner following administration of each treatment will be compared with the placebo. | 45 minutes following administration of each treatment / placebo |
| Differences of omission errors in Go-NoGo CPT following administration of each treatment and the placebo | L-theanine, caffeine, L-theanine-caffeine combination and placebo will be administered on 4 separate days (at least 5 days apart) in a random counter-balanced order. Differences of omission errors of the Go-NoGo continuous performance task performed in the magnetic resonance imaging scanner following administration of each treatment will be compared with the placebo. | 60 minutes following administration of each treatment / placebo |
| Differences of performance in Picture Sequence Memory Test following administration of each treatment and the placebo | L-theanine, caffeine, L-theanine-caffeine combination and placebo will be administered on 4 separate days (at least 5 days apart) in a random counter-balanced order. Differences of performance in Picture Sequence Memory Test of the NIH Toolbox Cognition Battery following administration of each treatment will be compared with the placebo. | 100 minutes following administration of each treatment / placebo |
| Differences of performance in List Sorting Working Memory Test following administration of each treatment and the placebo | L-theanine, caffeine, L-theanine-caffeine combination and placebo will be administered on 4 separate days (at least 5 days apart) in a random counter-balanced order. Differences of performance in List Sorting Working Memory Test of the NIH Toolbox Cognition Battery following administration of each treatment will be compared with the placebo. | 100 minutes following administration of each treatment / placebo |
| ID | Term |
|---|---|
| D001289 | Attention Deficit Disorder with Hyperactivity |
| ID | Term |
|---|---|
| D019958 | Attention Deficit and Disruptive Behavior Disorders |
| D065886 | Neurodevelopmental Disorders |
| D001523 | Mental Disorders |
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| ID | Term |
|---|---|
| C026166 | theanine |
| D002110 | Caffeine |
| ID | Term |
|---|---|
| D014970 | Xanthines |
| D000470 | Alkaloids |
| D006571 | Heterocyclic Compounds |
| D011688 | Purinones |
| D011687 | Purines |
| D006574 | Heterocyclic Compounds, 2-Ring |
| D000072471 | Heterocyclic Compounds, Fused-Ring |
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