NCT07189442Completed
L-theanine and Paraxanthine for Cognitive Improvement in Adults With ADHD and ASD
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
Source: ClinicalTrials.gov · Last updated 24 Aug 2026
Brief summary (registry, in English)
This pilot study will test whether combining L-theanine and paraxanthine improves sustained attention, inhibitory control, and overall cognition in adults with ADHD and ASD. Two parallel randomized, single-blinded, repeated-measures crossover trials will be conducted. Participants will complete neuropsychological testing, fMRI scanning, and self-report measures following administration of the L-theanine-paraxanthine combination compared to placebo.
- Status (registry)
- Completed
- Study type
- Interventional
- Enrollment
- 17 (actual)
- First submitted
- 16 Sept 2025
- Start date
- 1 Oct 2025
- Primary completion date
- 1 Jun 2026
- Lead sponsor
- Texas Tech University Health Sciences Center
- Diseases
- Autism
- NCT number
- NCT07189442
What you commit to
- Study type: Interventional
- Participants enrolled: 17
- From 1 Oct 2025 to the primary completion date, 1 Jun 2026
- 1 site in 1 country
- Visits and tests: ask the trial team, the registry does not list them
Built from the registry fields of ClinicalTrials.gov. It describes the study, not your situation.
Who cannot take part
Copied verbatim from ClinicalTrials.gov and grouped by topic. Only the trial team decides who can take part.
Prior treatment
- Subjects on medications including antidepressants and antipsychotics that may affect performance in the tasks
- 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)
- 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
- Intake of drugs containing caffeine, other phosphodiesterase inhibitors, or adenosine receptor blockers within the past 3 months
- Intake of medications known to have pharmacological interactions with paraxanthine within the past 3 months
Other illness
- Physical, neurological, intellectual, or psychiatric impairments (except ADHD or ASD) that could affect cognitive and motor functions
- History of head injury resulting in loss of consciousness/history of brain surgery
- History of headache, drowsiness, anxiety, insomnia, or nausea following intake of caffeine or caffeine-containing beverages
- Current/past history of smoking and/or alcohol or drug abuse
Other
- Subjects with gross visual or auditory impairments that might limit their ability to perform neuropsychological tasks
- Inability to read and follow written instructions
- Subjects who have developed adverse effects when caffeine/paraxanthine /L-theanine/corn starch (will be in placebo) containing products were consumed
- Current/past diagnosis of tics or other forms of dyskinesia
- Subjects with absolute contraindications to undergo MRI after being screened by the TTNI safety screening sheet (Appendix)
- Unwillingness or inability to entirely refrain from the use of electronic devices during study visits
- Unwillingness or inability to follow written, on-screen, and verbal instructions given by the study team.
Who the study is looking for
- 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
Sex: Male · Does not accept healthy volunteers
Sites (1)
Sites in registry order. Pick your city on the disease page to sort them by distance.
| Site | City | Country | Site status |
|---|---|---|---|
| Texas Tech University Coordinator of this site? Confirm its status | Lubbock | United States | Unknown status |
This page is information, not medical advice. Discuss any trial with your doctor.