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Clinical trialNCT04013555CompletedPhase 1/PHASE2Interventional

The Effects of Kynurenine Aminotransferase Inhibition in People With Schizophrenia

SponsorUniversity of Maryland, BaltimoreEnrollment88Schizoaffective DisorderSchizophreniaSchizophreniform Disorder
View the registry record on ClinicalTrials.gov

Summary

The lay summary the sponsor registered on ClinicalTrials.gov.

Kynurenic acid (KYNA) is a naturally occurring chemical in the brain. Studies with rodents indicate that levels of KYNA can impact levels of the neurotransmitters glutamate and dopamine. One way to reliably increase KYNA levels is by ingesting the amino acid tryptophan. Tryptophan is a normal part of the human diet. Tryptophan gets metabolized/changed to other chemicals in the body- including KYNA. By giving people 6 grams of tryptophan, the investigators will be able to increase the KYNA level in a controlled way. The investigators will then be able to study the effects of KYNA on neurotransmitters by using cognitive tests and magnetic resonance imaging techniques (measuring brain activity and brain chemistry using the MRI magnet). The overall goal of the study is to examine how the medication N-acetylcysteine (NAC), when added to tryptophan, affects various cognitive functions, such as verbal and visual memory. The investigators will also use magnetic resonance imaging (MRI) to examine how NAC affects brain activity and chemicals.
clinicaltrials.gov ↗

Investigators

The overall officials registered on this study. Names that resolve to a findmyKOL profile link to it; the rest are shown as registered.

A profile link is shown only when the registered name resolves to a person record with a confident, namesake-checked match; ambiguous names stay unlinked.

Sites

1 registered facility, with the per-site recruitment status where the registry publishes one. ClinicalTrials.gov does not publish per-site enrollment counts.

United States
  • Maryland Psychiatric Research Center (mprc) ; the Treatment Research Program (trp)

    Catonsville, Maryland, United States

Site investigator names are published by ClinicalTrials.gov only while a study recruits, so completed studies list sites without them.

Drugs studied

The drug and biological interventions registered on this study, normalized to their RxNorm ingredient where possible.

Acetylcysteine →PlaceboTryptophan
Linked drugs open the directory filtered to KOLs working with them.clinicaltrials.gov ↗

Registration & key dates

Registry attributes as recorded on the ClinicalTrials.gov study record.

Start
20 Jan 2020
Primary completion
14 Aug 2024
Completion
14 Aug 2024
Last update posted
11 Feb 2026
Registered enrollment
88
Registry id
NCT04013555
clinicaltrials.gov ↗

Source: ClinicalTrials.gov, via the CTTI AACT database, data as of 24 Aug 2026. Registry facts are shown as registered by the study sponsor; findmyKOL does not interpret them.