RecruitingNot ApplicableNCT07189442

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

Sponsor

Texas Tech University Health Sciences Center

Enrollment

24 participants

Start Date

Oct 1, 2025

Study Type

INTERVENTIONAL

Conditions

Attention Deficit Hyperactivity Disorder (ADHD)Autism Spectrum Disorder (ASD)

Summary

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.

Eligibility

Sex: MALE

Inclusion Criteria2

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 Criteria16

Subjects with gross visual or auditory impairments that might limit their ability to perform neuropsychological tasks
Inability to read and follow written instructions
Physical, neurological, intellectual, or psychiatric impairments (except ADHD or ASD) that could affect cognitive and motor functions
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)
History of head injury resulting in loss of consciousness/history of brain surgery
Subjects who have developed adverse effects when caffeine/paraxanthine /L-theanine/corn starch (will be in placebo) containing products were consumed
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
Current/past diagnosis of tics or other forms of dyskinesia
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
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.