Tryptophan-Kynurenine Pathway Metabolism in the Pathophysiology of Cognitive Impairment in Schizophrenia.

An observational study of Schizophrenia, run by Tianjin Anding Hospital at 1 site in China.

Enrolling by invitation

Enrolling by invitation. The study team selects and invites participants, usually from an existing group of patients.

Sites and contacts

Official record

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Trial summary

Who is it for?: Ages 18 to 55 yearsHealthy volunteers can take part
Conditions the study is for: Schizophrenia
How many people: 200 participants
Where: 1 siteChina
Study dates: 19 Feb 2024to 30 Jun 2026
How long will I take part?: 8 Weeks
Phase: Observational
Are there results?: Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 18 to 55 years
All sexes
Healthy volunteers accepted
Adult

Study population: This study will recruit 100 Han Chinese adults aged 18-55 years for two cohorts: patients and healthy controls. The patient cohort will comprise individuals experiencing their first episode of schizophrenia or schizophreniform disorder with a duration of ≤ 5 years, who have either never received antipsychotic treatment or have received it for a cumulative duration of ≤ 4 weeks prior to enrollment. Recruitment will be conducted from the outpatient and inpatient services of Tianjin Anding Hospital and surrounding communities in Tianjin, China. The healthy control cohort will consist of 100 Han Chinese adults matched to the patient group for sex, age, and education. These individuals must have no personal or family history of major psychiatric disorders and demonstrate no cognitive impairment on formal testing.

Who may be able to join

Healthy volunteers matched to the patient group on sex, age, and education level;
Ethnic Han Chinese;
Able and willing to provide written informed consent.

Who cannot join

Significant comorbid medical or neurological conditions;
Any DSM-5-defined psychiatric disorder;
Family history of psychiatric illness spanning three or more generations;
Current use of psychoactive medications;
Refusal to provide informed consent/participate.

Trial locations and contacts

1 site in 1 country. Contact the study team or a site near you to ask about taking part.

China1 site

Tianjin Anding Hospital
Tianjin

Other trials in China

About this study

Schizophrenia is a common, long-term mental illness. It causes problems with thoughts, feelings, and behavior, including positive symptoms (hallucinations, delusions), negative symptoms (lack of emotion, motivation), and cognitive impairment (trouble with thinking, memory, and attention). While antipsychotic drugs effectively treat positive symptoms, they don't help much with cognitive impairment.This study will examine how the tryptophan-kynurenine pathway in the brain contributes to cognitive problems in people having their first episode of schizophrenia and treated with a single antipsychotic. Our goal is to create models for early detection of cognitive impairment in schizophrenia and find potential targets for new treatments to improve thinking and memory.

Read the detailed description

This single-center, prospective study will recruit 100 treatment-naïve, first-episode schizophrenia (SZ) patients at Tianjin Anding Hospital for an 8-week follow-up. All patients will receive monotherapy with risperidone and undergo baseline and week 8 assessments including clinical rating scales and the MATRICS Consensus Cognitive Battery (MCCB), along with peripheral blood sample collection. Concurrently, 100 age-, sex-, and education-matched healthy controls (HCs) will be recruited. Prior data from 300 medication-naïve SZ patients and 100 HCs will be selectively included in the final analysis (totaling 300 SZ patients and 200 HCs). We hypothesize that dysregulation of the tryptophan-kynurenine (TRP-KYN) pathway in SZ patients, leading to an imbalanced ratio of neuroprotective kynurenic acid (KYNA) to neurotoxic quinolinic acid (QUIN), affects inflammatory markers and NMDA receptor (NMDAR) levels, ultimately causing cognitive impairment. Specifically, we will analyze the association between cognitive function and plasma TRP-KYN pathway metabolites in medication-naïve FES patients; relationship between cognitive function and TRP-KYN pathway gene polymorphisms and mRNA expression in medication-naïve FES patients; and changes in cognitive function post-8-week treatment with plasma TRP-KYN pathway mRNA expression and metabolite levels.

Conditions: Schizophrenia
Keywords: schizophrenia, cognitive funciton, tryptophan-kynurenine pathway
Medical subject headings: Schizophrenia

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Study groups in NCT07162467
Study group	Role	What they receive
Schizophrenic Patients		100 eligible individuals will meet DSM-5 criteria for schizophrenia or schizoaffective disorder, be Han Chinese aged 18-55 years, presenting with a first episode of illness ≤ 5 years duration. Prior antipsychotic exposure must be ≤ 4 weeks cumulatively, or patients must be treatment-naïve. Informed consent will be obtained from patients and their families.
Healthy Control		100 healthy, age-, gender-, and education-matched Han Chinese volunteers, with informed consent.

What is being measured

The primary outcome is the main question the study is designed to answer.

TRP-KYN pathway candidate plasma metabolite levels
Plasma levels of tryptophan-kynurenine (TRP-KYN) pathway candidate metabolites, including kynurenine, kynurenic acid, kynurenic quinolinic acid, quinolinic acid, tryptophan, indole-3-acetic acid, and indole-3-propionic acid, were quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Sample information was registered in MetLIMS software, with designated positions for samples of interest, blanks, standards, and quality control samples. Samples were added to corresponding wells in a 96-well plate provided in the kit. Subsequently, derivatization was performed by adding a 5% phenylisothiocyanate solution. Finally, target analytes were extracted with an organic solvent and diluted. The pre-processed sample extracts underwent High-Performance Liquid Chromatography-Mass Spectrometry detection. Each sample was analyzed in two parts: the first involved signal acquisition in flow injection analysis mode, and the second in liquid chromatography-mass spectrometry mode.
Measured: Baseline, week8
Cognitive Function
All participants underwent cognitive function assessment based on the MATRICS Consensus Cognitive Battery (MCCB). The MCCB is a standardized instrument for assessing cognitive function in schizophrenia. It comprises nine subtests primarily evaluating seven cognitive domains: processing speed, attention/alertness, working memory, verbal learning, visual memory, reasoning and problem-solving, and social cognition. The MCCB scoring procedure generates standardised T-scores that are corrected for age, gender, and educational level. Higher T-scores indicate better cognitive function.
Measured: Baseline, week8
Candidate gene mRNA expression levels
Whole blood was collected in BD PAXgene® Blood RNA tubes (2.5 mL from antecubital veins) and gently inverted to mix. Samples were incubated vertically at room temperature for 2 hours, then stored at -20°C overnight before transfer to -80°C for RNA extraction. Extracted RNA was reverse transcribed to synthesize cDNA. Gene expression levels of TDO, IDO, KMO, KAT-II, KYNU, and 3HAO were determined by RT-qPCR with gel electrophoresis for product validation and densitometric scanning using a gel imaging system.
Measured: Baseline, week8

Secondary outcomes (4)

Psychiatric Symptoms
The psychiatric symptoms of schizophrenia were assessed in all enrolled patients using the Positive and Negative Syndrome Scale (PANSS). The PANSS is a 30-item clinician-rated scale yielding a total score ranging from 30 (least symptomatic) to 210 (symptomatic), where higher scores indicate more severe psychopathology.
Measured: Baseline, week8
Depressive Symptoms
The Hamilton Depression Scale-24 (HAMD-24) was used to assess the severity of depressive symptoms. Each item was scored on a scale of 0 (none) to 4 (severe); the total score ranged from 0 to 76, with higher scores indicating more severe depressive symptoms.
Measured: Baseline, week8
Anxiety Symptoms
The Hamilton Anxiety Scale (HAMA) is used to assess the severity of anxiety symptoms. Each item is scored on a scale of 0 (none) to 4 (very severe), with a total score range of 0-56. Higher scores indicate more severe anxiety symptoms.
Measured: baseline, week 8
Clinical Global Impression of Efficacy
The Clinical Global Impression (CGI) scale is used to assess treatment outcomes in patients, particularly for monitoring efficacy in severe mental disorders such as schizophrenia. The CGI encompasses three core dimensions: Severity of Illness (SI), Global Improvement (GI), and an Efficacy Index (EI). The CGI provides a structured assessment framework for healthcare professionals through a quantitative scoring system. In particular, the CGI-EI integrates therapeutic effects with adverse events, resulting in a graded assessment ranging from 0 (Markedly worse) to 4 (Markedly improved), suitable for monitoring during the entire course of treatment.
Measured: baseline, week 8

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

19 Feb 202430 Jun 2026

First posted9 Sep 2025
Study start19 Feb 2024
Primary completion1 Jun 2026 (estimated)
Study completion30 Jun 2026 (estimated)

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Other trials for SchizophreniaStudies of the same condition, open and under way.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Observational
Observational model: Cohort
Time perspective: Prospective
Enrolment: 200 participants (estimated)
Target duration: 8 Weeks

IDs, dates and publications

ClinicalTrials.gov ID: NCT07162467
Sponsor's protocol ID: FESW-TKAH
Status last verified: Jan 2026
First submitted: 31 Aug 2025
Last updated: 14 Jan 2026
Results posted: No
Data monitoring committee: Yes
FDA-regulated drug: No
FDA-regulated device: No

Interested in taking part?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See sites and contacts

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All Schizophrenia trials

Study at a glance

From the registry record, last updated by the sponsor on 14 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Tryptophan-Kynurenine Pathway Metabolism in the Pathophysiology of Cognitive Impairment in Schizophrenia.
ClinicalTrials.gov ID: NCT07162467
Acronym / sponsor ID: FESW-TKAH
Conditions: Schizophrenia
Keywords: schizophrenia, cognitive funciton, tryptophan-kynurenine pathway
Study type: Observational
Recruitment status: Enrolling by invitation
Enrolment: 200 participants (estimated)
Lead sponsor: Tianjin Anding HospitalUniversity, hospital or other
Study start: 19 Feb 2024 (actual)
Primary completion: 1 Jun 2026 (estimated)
Study completion: 30 Jun 2026 (estimated)
First posted: 9 Sep 2025 (actual)
Results: Not posted in the source record

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Detailed description

Study design

Observational model: Cohort
Time perspective: Prospective
Target follow-up: 8 Weeks
Number of arms: 2

Arm	Type	Receives
Schizophrenic Patients	–	–100 eligible individuals will meet DSM-5 criteria for schizophrenia or schizoaffective disorder, be Han Chinese aged 18-55 years, presenting with a first episode of illness ≤ 5 years duration. Prior antipsychotic exposure must be ≤ 4 weeks cumulatively, or patients must be treatment-naïve. Informed consent will be obtained from patients and their families.
Healthy Control	–	–100 healthy, age-, gender-, and education-matched Han Chinese volunteers, with informed consent.

Who may qualify

Ages: 18 to 55 years
Sex: All
Healthy volunteers: Accepted
Age groups: Adult
Study population: This study will recruit 100 Han Chinese adults aged 18-55 years for two cohorts: patients and healthy controls. The patient cohort will comprise individuals experiencing their first episode of schizophrenia or schizophreniform disorder with a duration of ≤ 5 years, who have either never received antipsychotic treatment or have received it for a cumulative duration of ≤ 4 weeks prior to enrollment. Recruitment will be conducted from the outpatient and inpatient services of Tianjin Anding Hospital and surrounding communities in Tianjin, China. The healthy control cohort will consist of 100 Han Chinese adults matched to the patient group for sex, age, and education. These individuals must have no personal or family history of major psychiatric disorders and demonstrate no cognitive impairment on formal testing.

Key inclusion criteria (3 listed)

Healthy volunteers matched to the patient group on sex, age, and education level;
Ethnic Han Chinese;
Able and willing to provide written informed consent.

Key exclusion criteria (5 listed)

Significant comorbid medical or neurological conditions;
Any DSM-5-defined psychiatric disorder;
Family history of psychiatric illness spanning three or more generations;
Current use of psychoactive medications;
Refusal to provide informed consent/participate.

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Primary outcome

TRP-KYN pathway candidate plasma metabolite levels
Time frame: Baseline, week8
Plasma levels of tryptophan-kynurenine (TRP-KYN) pathway candidate metabolites, including kynurenine, kynurenic acid, kynurenic quinolinic acid, quinolinic acid, tryptophan, indole-3-acetic acid, and indole-3-propionic acid, were quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Sample information was registered in MetLIMS software, with designated positions for samples of interest, blanks, standards, and quality control samples. Samples were added to corresponding wells in a 96-well plate provided in the kit. Subsequently, derivatization was performed by adding a 5% phenylisothiocyanate solution. Finally, target analytes were extracted with an organic solvent and diluted. The pre-processed sample extracts underwent High-Performance Liquid Chromatography-Mass Spectrometry detection. Each sample was analyzed in two parts: the first involved signal acquisition in flow injection analysis mode, and the second in liquid chromatography-mass spectrometry mode.
Cognitive Function
Time frame: Baseline, week8
All participants underwent cognitive function assessment based on the MATRICS Consensus Cognitive Battery (MCCB). The MCCB is a standardized instrument for assessing cognitive function in schizophrenia. It comprises nine subtests primarily evaluating seven cognitive domains: processing speed, attention/alertness, working memory, verbal learning, visual memory, reasoning and problem-solving, and social cognition. The MCCB scoring procedure generates standardised T-scores that are corrected for age, gender, and educational level. Higher T-scores indicate better cognitive function.
Candidate gene mRNA expression levels
Time frame: Baseline, week8
Whole blood was collected in BD PAXgene® Blood RNA tubes (2.5 mL from antecubital veins) and gently inverted to mix. Samples were incubated vertically at room temperature for 2 hours, then stored at -20°C overnight before transfer to -80°C for RNA extraction. Extracted RNA was reverse transcribed to synthesize cDNA. Gene expression levels of TDO, IDO, KMO, KAT-II, KYNU, and 3HAO were determined by RT-qPCR with gel electrophoresis for product validation and densitometric scanning using a gel imaging system.

4 secondary outcomes

Psychiatric Symptoms
Time frame: Baseline, week8
Depressive Symptoms
Time frame: Baseline, week8
Anxiety Symptoms
Time frame: baseline, week 8
Clinical Global Impression of Efficacy
Time frame: baseline, week 8

Results and safety

This study is still under way. Results are not available in the source record yet.

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 14 Jan 2026.

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Deep Brain Stimulation for Treatment-Resistant Schizophrenia
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Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.

The record lists no contact. Use the official record to reach the sponsor.

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

An observational study of Schizophrenia, run by Tianjin Anding Hospital at 1 site in China.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 3 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: enrolling by invitation, as of the sponsor's last update on 14 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in China. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

TRP-KYN pathway candidate plasma metabolite levels (time frame: Baseline, week8). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07162467.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 14 Jan 2026.