Neurotransmitters in Treatment Resistant Schizophrenia Patients With add-on Sodium Benzoate

June 14, 2026 updated by: National Cheng-Kung University Hospital

Functional Connectivity and Associated Neuropeptides Variations in Treatment Resistant Schizophrenia Patients: Treatment Efficacy of add-on Sodium Benzoate

Although antipsychotic is effective for schizophrenia, however, still certain proportion of patients were not responsive to treatment. Treatment resistant schizophrenia (TRS) is accompanied by function decline and heavy burden. In recent decades, the biological mechanism of schizophrenia extended from dopamine theory to the role of glutamate system. This shift could be an alternative pathway to developing the treatment of TRS. Sodium benzoate (SB) could be an option as a glutamatergic agent for the patients with TRS. However, most evidence of SB is for treating patients with schizophrenia and other mental disorders but the evidence for treating patients with TRS is scarce. To predict the treatment response of SB will be an urgent topic in the future. Little is known about the precise medicine for treating patients with TRS. The present project will extend our pilot randomized clinical trial on SB for TRS. A total of 90 patients with TRS will be enrolled from three centers and will be assigned to 8 weeks of treatment with SB or placebo (2:1). A comprehensive battery of potential markers will be employed, including 1H- magnetic resonance spectroscopy (MRS), brain functional connectivity, genotyping, immune biomarkers, cognitive function, and clinical characteristics. The efficacy of SB on TRS will be confirmed in this project. Predictors for treatment response will be identified. Artificial intelligence algorithms will be used for probing the feasibility of precision medicine.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The design and instrument are identical for two years. This add-on sodium benzoate randomized, double-blinded, placebo-controlled trial which is a two-arm, 6-week follow-up trial. The 90 patients will be 2:1 (SB: placebo) randomly assigned to 1. Treatment with sodium benzoate (A); or 2. placebo (P). The group of sodium benzoate treatment will be divided into two subgroups: 1. Responder (AR), and nonresponder (AN), as illustrated in Figure 4. The response criteria is defined the improvement of 20% total PANSS score after 6-week SB treatment. The participants with TRS will be enrolled in this trail from 3 hospitals(National Cheng Kung University Hospital, Tainan Hospital, Ministry of Health and Welfare, Chia-Yi branch, Taichung Veteran General Hospital).

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
90

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • Taiwan
      • Chiayi City, Taiwan, 600
        • Recruiting
        • Taichung Veterans General Hospital Chiayi Branch
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Fulfil the DSM5 criteria for schizophrenia or schizoaffective disorder
  2. Research criteria for treatment resistance: little or no symptomatic response to multiple (at least two) antipsychotic treatment of an adequate duration (at least 6 weeks) and adequate doses (equivalent to at least 600 milliequivalent (meq)/day of chlorpromazine)
  3. 6 month period without remission (i.e. ≥4 item-score for the positive symptoms on PANSS scale , especially delusional thoughts, conceptual disorganisation, excitements, grandiosity, hallucinatory behaviour, excitement, persecution, and hostility)
  4. The persistence of illness was defined as a score of ≥4 (moderately ill) on the severity of illness subscale of the Clinical Global Impression scale (CGI-S), and a lack of stable period of good social occupational function.

Exclusion Criteria:

  1. Current or previous diagnosis of concurrent DSM-5 disorder due to active medical problems, known neurological disease, or a contraindication to MRI scanning
  2. Current diagnosis of substance-related disorder
  3. Any acute or chronic medical condition
  4. History of head trauma or neurological diseases.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Treatment resistant schizophrenia patients with augmentation of sodium benzoate 2g/day
with sodium benzoate 2g/day
Drug: Sodium Benzoate 2gram/day
the add-on sodium benzoate with conventional pharmacological treatment
Placebo Comparator: Treatment resistant schizophrenia patients with augmentation of placebo
with placebo
Drug: Placebo
the add-on placebo with conventional pharmacological treatment

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Brain imaging, functional MRI
Time Frame: 1hours
All participants were scanned using a 1.5 Tesla GE scanner with eight channel head coils. 1H-MRS was performed to assess the concentrations of excitatory, glutamine, glutamate, glutamate complex (Glx), GABA and other neurometabolites. A three-dimensional T1-weighted inversion recovery magnetic resonance imaging (MRI) scan was performed in all participants, axial MRI three-dimensional brain volume, echo time (TE) = 2.9 ms, repetition time (TR) = 7.7, inversion time = 450 ms, flip angle = 12°, field of view =230 mm, matrix size = 256 × 256, and slice thickness = 1.0 mm
1hours

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Clinical psychiatric condition, Positive and Negative Symptoms Scale (PANSS)
Time Frame: 20 minutes
The PANSS is a clinical tool used to measure symptom severity in patients with schizophrenia. It takes approximately 45 minutes to interview a patient with schizophrenia using the PANSS. The patient is rated from 1 to 7 on 30 different symptoms based on the interview, as well as descriptions of caregivers or hospital workers. There are seven positive symptoms, seven negative symptoms, and 16 general psychopathological traits.
20 minutes
Wechsler adult intelligence scales 4th edition (WAIS-IV)
Time Frame: 1 hours
Specifically, for the cognitive function measurement, the WAIS-IV scale was used that comprises of five items: full-scale IQ (FSIQ), verbal comprehension index (VCI), perceptual reasoning index (PRI), WMI, and processing speed index (PSI), all of which are presented as different aspects of cognitive evaluation.
1 hours
Continuous performance test third edition (CPT-3)
Time Frame: 20 minutes
The CPT-3, is a computer assessment that evaluates attention-related deficits generally performed in ADHD. The test requires examinees to press the space bar when any letter appears, except for the letter "X." The entire test has 360 trials and takes approximately 14 minutes to administer. CPT-3 yields 10 Tscores: Omissions (OM), Variability (VAR), Commissions (COM), Perseveration (PER), Detectability (DET), Response Style (RS), Hit Reaction Time (HRT), HRT Block Change (BC), HRT Standard Deviation (HRT SD), and HRT Inter-Stimulus Interval (ISI) change, based on four different domains of attention: inattentiveness, impulsivity, sustained attention, and vigilance. The CPT-3 also includes an internal validity check which notifies the administrator that the administration is invalid if the examinee had too few hits on targets, an omission rate higher than 25%, or if there was a timing problem regarding administration.
20 minutes
Wisconsin card sorting test (WCST)
Time Frame: 20 minutes
WCST Computer Version 4-Research Edition was used in this study, and patients were required to match response cards to four stimulus cards along one of three dimensions (colour, form, or number) on the basis of verbal feedback (correct or wrong) without providing any information about the dimensions. Once the subject sorted a series of 10 cards into one category, the subject was asked to sort the cards again by a different category. In the present study, 64 cards were used. All definitions of the indices have been described in the WCST manual.
20 minutes

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
National Cheng-Kung University Hospital

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Yen-Kuang Yang, Dr, Psychiatry department, National Cheng Kung University Hospital, Tainan, Taiwan

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 18, 2021

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
April 30, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
April 30, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
November 3, 2021

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 29, 2024

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
April 2, 2024

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 16, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 14, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • A-BR-110-049

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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