SchizophreniaNCT07393464
PQQ for Cognitive and Negative Symptoms
A study testing Pyrroloquinoline quinone (PQQ) in people with Schizophrenia and Cognitive Symptoms, run by Tianjin Anding Hospital.
Trial summary
Schizophrenia is a complex mental disorder characterized by a range of symptoms, including negative symptoms and cognitive impairments. Recent research has indicated the potential benefits of targeting mitochondrial dysfunction, oxidative stress, and inflammatory responses in alleviating symptoms of schizophrenia. Read more about this study
- Who is it for?
- Ages 18 to 50 years
- Conditions the study is for
- Schizophrenia, Cognitive Symptoms, Negative Symptoms
- What is being tested?
- Pyrroloquinoline quinone (PQQ)
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 70 participants
- Where
- No sites listed yet
- Study dates
- 15 Feb 2026to 15 Apr 2028
- Phase
- Interventional
- 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 50 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- Eligible male and female patients aged 18 to 50 years, diagnosed with schizophrenia according to the criteria outlined in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5), will be included in the study. Participants are required to meet the following criteria: a Positive and Negative Syndrome Scale (PANSS) total scores of ≥ 60 (indicating an active phase of the illness), a PANSS negative subscale scores of ≥ 20, and a duration of illness of at least 2 years (indicating chronic schizophrenia). Additionally, participants must have been on a stable dose of antipsychotic medication for a minimum of 6 weeks prior to enrollment, and the use of antioxidants or anti-inflammatory medications is prohibited within 2 weeks preceding enrollment.
Who cannot join
- Patients with comorbid psychiatric disorders as defined by the DSM-5, such as substance abuse or dependence (excluding nicotine), or intellectual disability (IQ < 70); those with significant depressive symptoms, defined as a score ≥14 on the 17-item Hamilton Depression Rating Scale (HAMD-17) or ≥ 4 on the depression item of PANSS; individuals with severe medical or neurological conditions, or those unable to communicate effectively; patients with a known allergy to PQQ disodium salt, or who are pregnant, breastfeeding, or have severe hepatic or renal impairment; women of childbearing potential who are not using reliable contraception; patients who have received modified electroconvulsive therapy (MECT) or other physical treatments within six months prior to enrollment; and those currently receiving treatments that cannot be discontinued, including antidepressants, mood stabilizers, antihistamines, or combination therapy with two or more antipsychotics (except for low-dose aripiprazole, ≤ 5 mg/day, used solely for prolactin reduction).
- Additional exclusion criteria for participants undergoing fMRI scanning:
- Participants are required to complete a comprehensive safety questionnaire addressing potential risks associated with exposure to a 3-Tesla magnetic field and the MRI environment. MRI-specific exclusion criteria include: the presence of MRI-incompatible implants (e.g., cochlear implants, insulin pumps, pacemakers, or other metallic implants); a history of possible intraocular metallic foreign bodies due to manual labor without appropriate eye protection; tattoos containing red pigments; claustrophobia; or unwillingness to be informed of any incidental structural brain abnormalities detected during the scan.
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
Daxiang Medical Ethics Committee of Tianjin Anding Hospital contact
About this study
Official title: The Efficacy and Safety of Pyrroloquinoline Quinone add-on Treatment for Negative and Cognitive Symptoms in Chronic Schizophrenia
Schizophrenia is a complex mental disorder characterized by a range of symptoms, including negative symptoms and cognitive impairments. Recent research has indicated the potential benefits of targeting mitochondrial dysfunction, oxidative stress, and inflammatory responses in alleviating symptoms of schizophrenia. However, the results remain inconsistent across various studies. This study aims to evaluate the efficacy of Pyrroloquinoline quinone (PQQ) in reducing negative symptoms and improving cognitive function in patients with chronic schizophrenia. The investigation will focus on changes in severity scores from baseline to endpoint, as well as during an eight-week follow-up period. A double-blind, randomized controlled trial will be conducted involving participants diagnosed with chronic schizophrenia. Participants will be randomly assigned to receive either PQQ or a matched placebo. Data will be collected through questionnaires and neuroimaging techniques, including resting-state scans and multimodal tasks to assess functional connectivity and activation in target brain regions. Statistical analyses will include descriptive statistics, voxel-by-voxel multiple regression, and linear mixed models to account for repeated measurements. Additionally, potential moderating effects of demographic factors such as age and gender will be examined using ANCOVAs. The study will also monitor adverse events and ensure participant safety through a rigorous reporting and unblinding procedure. It is hope to provide insights into the therapeutic potential of PQQ in managing schizophrenia symptoms, contributing to the development of more effective treatment strategies for this challenging condition.
- Conditions
- Schizophrenia, Cognitive Symptoms, Negative Symptoms
- Being tested
- Pyrroloquinoline quinone (PQQ), placebo (dietary fiber)
- Keywords
- cognitive symptom, negative symptom, schizophrenia, Pyrroloquinoline Quinone, MCCB
- Medical subject headings
- Schizophrenia, Neurobehavioral Manifestations
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Pyrroloquinoline quinone (PQQ)Dietary supplement
Patients with chronic schizophrenia in experimental group will take 20 mg of PQQ orally every day for a total of 12 weeks.
placebo (dietary fiber)Dietary supplement
Patients with chronic schizophrenia in control group will a capsule of placebo orally every day for a total of 12 weeks.
| Study group | Role | What they receive |
|---|---|---|
| PQQ group | Experimental | Not described Receives: Dietary Supplement: Pyrroloquinoline quinone (PQQ) |
| Control group | Placebo comparator | Not described Receives: Dietary Supplement: placebo (dietary fiber) |
What is being measured
The primary outcome is the main question the study is designed to answer.
cognitive symptoms
the changes in scores of MCCB between the baseline and the first post-treatment measurement.
Measured: From enrollment to the end of 12 weeks
negative symptoms
the changes in scores of PANSS negative subscale between the baseline and the first post-treatment measurement.
Measured: From enrollment to the end of 12 weeks
Secondary outcomes (3)
congtive/negative symptoms
the scores of MCCB/PANSS negative subscale at the eight-week follow-up after withdrawal of PQQ treatment
Measured: From enrollment to the end of 20 weeks
Malondialdehyde, Mitochondrial DNA, and Glutathione Peroxidase
The levels of biomarkers representing oxidative stress and inflammatory activity are assessed in venous blood.
Measured: From enrollment to the end of 12 weeks and 20 weeks
Connectivity strength of target neural circuits
The functional state of target brain regions and the connectivity strength of key neural circuits, including the prefrontal-parietal cognitive control network, the hippocampal-prefrontal memory circuit, and the thalamo-cortical information gating system.
Measured: From enrollment to the end of 12 weeks and 20 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Feb 2026
- Study start15 Feb 2026 (estimated)
- Primary completion15 Feb 2028 (estimated)
- Study completion15 Apr 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (4)Papers the sponsor has linked to this study.
- 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
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- RCT
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 70 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Tianjin Anding Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Yang Chenghao, Tianjin Anding Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07393464
- Sponsor's protocol ID
- TJPQQ2026
- Status last verified
- Feb 2026
- First submitted
- 31 Jan 2026
- Last updated
- 10 Feb 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: required the permission from the PI
Publications
Tamakoshi M, Suzuki T, Nishihara E, Nakamura S, Ikemoto K. Pyrroloquinoline quinone disodium salt improves brain function in both younger and older adults. Food Funct. 2023 Mar 6;14(5):2496-2501. doi: 10.1039/d2fo01515c.
PubMed 36807425Nunome K, Miyazaki S, Nakano M, Iguchi-Ariga S, Ariga H. Pyrroloquinoline quinone prevents oxidative stress-induced neuronal death probably through changes in oxidative status of DJ-1. Biol Pharm Bull. 2008 Jul;31(7):1321-6. doi: 10.1248/bpb.31.1321.
PubMed 18591768Zhang P, Xu Y, Li L, Jiang Q, Wang M, Jin L. In vitro protective effects of pyrroloquinoline quinone on methylmercury-induced neurotoxicity. Environ Toxicol Pharmacol. 2009 Jan;27(1):103-10. doi: 10.1016/j.etap.2008.08.010. Epub 2008 Sep 7.
PubMed 21783927Xiao L, Wang M, Li J, Wang H, Pu N, Bo X, Chen F, Zhou Y, Cheng Q. Pyrroloquinoline Quinone Preconditioning Alleviates Ischemic Cerebral Injury Through Antioxidant and Anti-Inflammatory Mechanisms. J Neuroimmune Pharmacol. 2025 Jul 23;20(1):75. doi: 10.1007/s11481-025-10234-1.
PubMed 40696055
Study at a glance
From the registry record, last updated by the sponsor on 10 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Efficacy and Safety of Pyrroloquinoline Quinone add-on Treatment for Negative and Cognitive Symptoms in Chronic Schizophrenia
- ClinicalTrials.gov ID
- NCT07393464
- Acronym / sponsor ID
- TJPQQ2026
- Conditions
- Schizophrenia, Cognitive Symptoms, Negative Symptoms
- Keywords
- cognitive symptom, negative symptom, schizophrenia, Pyrroloquinoline Quinone, MCCB
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 70 participants (estimated)
- Lead sponsor
- Tianjin Anding HospitalUniversity, hospital or other
- Study start
- 15 Feb 2026 (estimated)
- Primary completion
- 15 Feb 2028 (estimated)
- Study completion
- 15 Apr 2028 (estimated)
- First posted
- 6 Feb 2026 (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.
Schizophrenia is a complex mental disorder characterized by a range of symptoms, including negative symptoms and cognitive impairments. Recent research has indicated the potential benefits of targeting mitochondrial dysfunction, oxidative stress, and inflammatory responses in alleviating symptoms of schizophrenia. However, the results remain inconsistent across various studies. This study aims to evaluate the efficacy of Pyrroloquinoline quinone (PQQ) in reducing negative symptoms and improving cognitive function in patients with chronic schizophrenia. The investigation will focus on changes in severity scores from baseline to endpoint, as well as during an eight-week follow-up period. A double-blind, randomized controlled trial will be conducted involving participants diagnosed with chronic schizophrenia. Participants will be randomly assigned to receive either PQQ or a matched placebo. Data will be collected through questionnaires and neuroimaging techniques, including resting-state scans and multimodal tasks to assess functional connectivity and activation in target brain regions. Statistical analyses will include descriptive statistics, voxel-by-voxel multiple regression, and linear mixed models to account for repeated measurements. Additionally, potential moderating effects of demographic factors such as age and gender will be examined using ANCOVAs. The study will also monitor adverse events and ensure participant safety through a rigorous reporting and unblinding procedure. It is hope to provide insights into the therapeutic potential of PQQ in managing schizophrenia symptoms, contributing to the development of more effective treatment strategies for this challenging condition.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- RCT
| Arm | Type | Receives |
|---|---|---|
| PQQ group | Experimental | Dietary Supplement: Pyrroloquinoline quinone (PQQ) |
| Control group | Placebo comparator | Dietary Supplement: placebo (dietary fiber) |
Who may qualify
- Ages
- 18 to 50 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (1 listed)
- Eligible male and female patients aged 18 to 50 years, diagnosed with schizophrenia according to the criteria outlined in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5), will be included in the study. Participants are required to meet the following criteria: a Positive and Negative Syndrome Scale (PANSS) total scores of ≥ 60 (indicating an active phase of the illness), a PANSS negative subscale scores of ≥ 20, and a duration of illness of at least 2 years (indicating chronic schizophrenia). Additionally, participants must have been on a stable dose of antipsychotic medication for a minimum of 6 weeks prior to enrollment, and the use of antioxidants or anti-inflammatory medications is prohibited within 2 weeks preceding enrollment.
Key exclusion criteria (3 listed)
- Patients with comorbid psychiatric disorders as defined by the DSM-5, such as substance abuse or dependence (excluding nicotine), or intellectual disability (IQ < 70); those with significant depressive symptoms, defined as a score ≥14 on the 17-item Hamilton Depression Rating Scale (HAMD-17) or ≥ 4 on the depression item of PANSS; individuals with severe medical or neurological conditions, or those unable to communicate effectively; patients with a known allergy to PQQ disodium salt, or who are pregnant, breastfeeding, or have severe hepatic or renal impairment; women of childbearing potential who are not using reliable contraception; patients who have received modified electroconvulsive therapy (MECT) or other physical treatments within six months prior to enrollment; and those currently receiving treatments that cannot be discontinued, including antidepressants, mood stabilizers, antihistamines, or combination therapy with two or more antipsychotics (except for low-dose aripiprazole, ≤ 5 mg/day, used solely for prolactin reduction).
- Participants are required to complete a comprehensive safety questionnaire addressing potential risks associated with exposure to a 3-Tesla magnetic field and the MRI environment. MRI-specific exclusion criteria include: the presence of MRI-incompatible implants (e.g., cochlear implants, insulin pumps, pacemakers, or other metallic implants); a history of possible intraocular metallic foreign bodies due to manual labor without appropriate eye protection; tattoos containing red pigments; claustrophobia; or unwillingness to be informed of any incidental structural brain abnormalities detected during the scan.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Pyrroloquinoline quinone (PQQ)Patients with chronic schizophrenia in experimental group will take 20 mg of PQQ orally every day for a total of 12 weeks. | Dietary supplement | PQQ group |
| placebo (dietary fiber)Patients with chronic schizophrenia in control group will a capsule of placebo orally every day for a total of 12 weeks. | Dietary supplement | Control group |
Primary outcome
cognitive symptoms
Time frame: From enrollment to the end of 12 weeks
the changes in scores of MCCB between the baseline and the first post-treatment measurement.
negative symptoms
Time frame: From enrollment to the end of 12 weeks
the changes in scores of PANSS negative subscale between the baseline and the first post-treatment measurement.
3 secondary outcomes
congtive/negative symptoms
Time frame: From enrollment to the end of 20 weeks
Malondialdehyde, Mitochondrial DNA, and Glutathione Peroxidase
Time frame: From enrollment to the end of 12 weeks and 20 weeks
Connectivity strength of target neural circuits
Time frame: From enrollment to the end of 12 weeks and 20 weeks
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 10 Feb 2026.
- Background: PubMed 36807425Tamakoshi M, Suzuki T, Nishihara E, Nakamura S, Ikemoto K. Pyrroloquinoline quinone disodium salt improves brain function in both younger and older adults. Food Funct. 2023 Mar 6;14(5):2496-2501. doi: 10.1039/d2fo01515c.
- Background: PubMed 18591768Nunome K, Miyazaki S, Nakano M, Iguchi-Ariga S, Ariga H. Pyrroloquinoline quinone prevents oxidative stress-induced neuronal death probably through changes in oxidative status of DJ-1. Biol Pharm Bull. 2008 Jul;31(7):1321-6. doi: 10.1248/bpb.31.1321.
- Background: PubMed 21783927Zhang P, Xu Y, Li L, Jiang Q, Wang M, Jin L. In vitro protective effects of pyrroloquinoline quinone on methylmercury-induced neurotoxicity. Environ Toxicol Pharmacol. 2009 Jan;27(1):103-10. doi: 10.1016/j.etap.2008.08.010. Epub 2008 Sep 7.
- Background: PubMed 40696055Xiao L, Wang M, Li J, Wang H, Pu N, Bo X, Chen F, Zhou Y, Cheng Q. Pyrroloquinoline Quinone Preconditioning Alleviates Ischemic Cerebral Injury Through Antioxidant and Anti-Inflammatory Mechanisms. J Neuroimmune Pharmacol. 2025 Jul 23;20(1):75. doi: 10.1007/s11481-025-10234-1.
- Individual participant dataSharing planned: Yes. required the permission from the PI
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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.
Daxiang Medical Ethics Committee of Tianjin Anding Hospital contact
Questions about this trial
What is this clinical trial studying?
A study testing Pyrroloquinoline quinone (PQQ) in people with Schizophrenia and Cognitive Symptoms, run by Tianjin Anding Hospital.
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 1 inclusion and 3 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: opening soon, as of the sponsor's last update on 10 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. 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?
Contact Daxiang Medical Ethics Committee of Tianjin Anding Hospital (0086-22-88188631, tjadllwyh@126.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
cognitive symptoms (time frame: From enrollment to the end of 12 weeks). The study lists 2 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 NCT07393464, which also lists 4 linked publications.
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 10 Feb 2026.