L-theanine plus paraxanthine for improving attention and thinking in adults with ADHD or autism
Combining L-theanine and Paraxanthine for Transient Improvement of Cognitive Deficits Among Patients With Attention Deficit Hyperactivity Disorder and Autism Spectrum Disorder: A Series of Translational Pilot Neuroimaging Studies
This pilot will test whether taking L-theanine together with paraxanthine can improve attention, impulse control, and overall thinking in adults with ADHD or ASD.
Quick facts
| Phase | Not applicable |
|---|---|
| Study type | Interventional |
| Enrollment | 24 (estimated) |
| Sex | Male |
| Sponsor | Texas Tech University Health Sciences Center Academic / other |
| Locations | 1 site (Lubbock, Texas) |
| Trial ID | NCT07189442 on ClinicalTrials.gov |
What this trial studies
This is a pilot, randomized, single-blinded, repeated-measures crossover design with two parallel trials enrolling adults diagnosed with ADHD or ASD. Participants will receive the L-theanine–paraxanthine combination and placebo in separate sessions while completing neuropsychological tests, self-report measures, and fMRI scanning. The study compares performance and brain activity after the active combination versus placebo to see if sustained attention and inhibitory control improve. Exclusion criteria limit enrollment to participants without major sensory, intellectual, neurological, or psychiatric comorbidities and not taking contraindicated medications.
Who should consider this trial
Good fit: Adults aged 18 or older with a physician-diagnosed ADHD or ASD who can undergo neuropsychological testing and fMRI and are not taking prohibited medications are ideal candidates.
Not a fit: People under 18, those with major neurological or psychiatric comorbidities, gross sensory impairments, or on antidepressants/antipsychotics or other contraindicated medications are unlikely to be eligible or benefit from this protocol.
Why it matters
Potential benefit: If successful, the combination could offer a lower-cost, complementary option to help improve sustained attention and impulse control in adults with ADHD or ASD.
How similar studies have performed: Prior controlled studies report that L-theanine combined with caffeine can reduce mind-wandering and improve sustained attention in healthy adults, but using paraxanthine and testing this combination in ADHD or ASD adults is largely novel.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria: Adults (18+ years) diagnosed by a physician (per self-report) with ADHD or ASD \* Participants with a dual diagnosis and ASD and ADHD will be recruited but will only be included in the ASD group - their concurrent ADHD diagnosis will be included as an additional variable in exploratory analyses Exclusion Criteria: 1. Subjects with gross visual or auditory impairments that might limit their ability to perform neuropsychological tasks 2. Inability to read and follow written instructions 3. Physical, neurological, intellectual, or psychiatric impairments (except ADHD or ASD) that could affect cognitive and motor functions 4. Subjects on medications including antidepressants and antipsychotics that may affect performance in the tasks 5. Subjects on medications that are likely to interact with the administered substances, including regular intake of medication that could alter visual, auditory, cognitive, or motor functions (except stimulants) 6. History of head injury resulting in loss of consciousness/history of brain surgery 7. Subjects who have developed adverse effects when caffeine/paraxanthine /L-theanine/corn starch (will be in placebo) containing products were consumed 8. Subjects who are unwilling or unable to refrain from intake of L-theanine/ caffeine/ paraxanthine containing food or beverages within the 24 hours prior to each study visit 9. Intake of drugs containing caffeine, other phosphodiesterase inhibitors, or adenosine receptor blockers within the past 3 months 10. Intake of medications known to have pharmacological interactions with paraxanthine within the past 3 months 11. Current/past diagnosis of tics or other forms of dyskinesia 12. History of headache, drowsiness, anxiety, insomnia, or nausea following intake of caffeine or caffeine-containing beverages 13. Current/past history of smoking and/or alcohol or drug abuse 14. Subjects with absolute contraindications to undergo MRI after being screened by the TTNI safety screening sheet (Appendix) 15. Unwillingness or inability to entirely refrain from the use of electronic devices during study visits 16. Unwillingness or inability to follow written, on-screen, and verbal instructions given by the study team.
Where this trial is running
Lubbock, Texas
- Texas Tech University — Lubbock, Texas, United States (Recruiting)
Study contacts
- Study coordinator: Chathurika S Dhanasekara, MD, PhD
- Email: samudani.dhanasekara@ttuhsc.edu
- Phone: 806-743-2378
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.