Actively Recruiting
L-theanine and Paraxanthine for Cognitive Improvement in Adults With ADHD and ASD
Led by Texas Tech University Health Sciences Center · Updated on 2026-02-05
24
Participants Needed
1
Research Sites
34 weeks
Total Duration
On this page
Sponsors
T
Texas Tech University Health Sciences Center
Lead Sponsor
T
Texas Tech University
Collaborating Sponsor
AI-Summary
What this Trial Is About
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.
CONDITIONS
Official Title
L-theanine and Paraxanthine for Cognitive Improvement in Adults With ADHD and ASD
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Adults 18 years or older diagnosed by a physician (per self-report) with ADHD or ASD
- Participants with both ASD and ADHD will be included in the ASD group with ADHD noted as an additional variable
You will not qualify if you...
- Significant vision or hearing impairments limiting ability to perform cognitive tasks
- Unable to read or follow written instructions
- Physical, neurological, intellectual, or psychiatric impairments (except ADHD or ASD) affecting cognitive or motor functions
- Taking antidepressants, antipsychotics, or medications that may affect task performance
- Taking medications likely to interact with the study substances, except stimulants
- History of head injury with loss of consciousness or brain surgery
- History of adverse effects from caffeine, paraxanthine, L-theanine, or corn starch products
- Unwilling or unable to refrain from L-theanine, caffeine, or paraxanthine intake 24 hours before visits
- Use of caffeine, phosphodiesterase inhibitors, or adenosine receptor blockers within past 3 months
- Use of medications known to interact with paraxanthine within past 3 months
- Current or past diagnosis of tics or dyskinesia
- History of headache, drowsiness, anxiety, insomnia, or nausea after caffeine intake
- Current or past smoking, alcohol, or drug abuse
- Contraindications for MRI as per safety screening
- Unwilling or unable to refrain from electronic device use during visits
- Unwilling or unable to follow instructions from the study team
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
Trial Site Locations
Total: 1 location
1
Texas Tech University
Lubbock, Texas, United States, 79430
Actively Recruiting
Research Team
C
Chathurika S Dhanasekara, MD, PhD
CONTACT
C
Chanaka N Kahathuduwa, MD, PhD
CONTACT
How is the study designed?
Study Type
INTERVENTIONAL
Masking
SINGLE
Allocation
RANDOMIZED
Model
CROSSOVER
Primary Purpose
OTHER
Number of Arms
2
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