SchizophreniaNCT04267003
Effects of Brain Stimulation on Cognition, Oscillations and GABA Levels in Schizophrenia
A study testing Transcranial Direct Current Stimulation in people with Schizophrenia, run by University of California, Davis at 1 site in United States.
Trial summary
People with schizophrenia often have problems with attention, learning and memory and other cognitive abilities that interfere with their work and school performance. Unfortunately, even our best treatments often do not significantly reduce these cognitive problems. Read more about this study
- Who is it for?
- Ages 18 to 47 yearsHealthy volunteers can take part
- Conditions the study is for
- Schizophrenia
- What is being tested?
- Transcranial Direct Current Stimulation
- Type of treatment
- Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 160 participants
- Where
- 1 siteUnited States
- Study dates
- 9 Jan 2020to 31 Aug 2026
- 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 47 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Participants must be able to sufficiently speak and understand English so as to be able to understand and complete cognitive tasks.
- All subjects must have the ability to give valid informed consent.
- Diagnosis of schizophrenia, schizophreniform or schizoaffective disorder
- No medication changes in the prior month
- No medication changes anticipated in the upcoming month
- Stable outpatient or partial hospital status
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- Normal IQ (>70; IQ will be measured by administering the Wechsler Abbreviated Scale of
- Intelligence (WASI) test)
- Must not be currently taking the antipsychotic clozapine
Who cannot join
- Pacemakers
- Implanted electrical (brain and spinal) stimulators
- Implanted defibrillator
- Metallic implants
- Skin damage or skin conditions such as eczema at the sites where electrodes will be placed
- Hair styles hindering the placement of electrodes
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- Cranial pathologies
- Head trauma
- Epilepsy
- Mental retardation
- Any known history of neurological disorders (including epilepsy, amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), stroke, cerebral palsy, any DSM-5 axis I psychiatric disorder (for healthy control subjects), autism)
- Uncorrected vision problems that would hinder cognitive testing (this also pertains to subjects with color blindness in tasks where discriminating colored objects/items is necessary for successful performance)
- Pregnancy
- Substance dependence in the past six months
- Substance abuse in the past month
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Imaging Research Center
Sacramento, California, 95817
Molly Bainbridge, 916-734-3749, mebainbridge@ucdavis.edu
Cameron Carter, M.D.
About this study
Official title: Transcranial Direct Current Stimulation (tDCS) Studies of Cognition, Oscillations and GABA Levels in Schizophrenia
People with schizophrenia often have problems with attention, learning and memory and other cognitive abilities that interfere with their work and school performance. Unfortunately, even our best treatments often do not significantly reduce these cognitive problems. The current study investigates whether or not delivering a very small electrical current to people's foreheads (called, transcranial direct current stimulation; (tDCS)) might improve functioning in the front part of the brain and reduce these cognitive problems in people with schizophrenia. tDCS is non-invasive and has been shown to improve cognitive functioning in some preliminary studies. The current study will investigate whether giving tDCS during a task is more effective than giving it during rest (Aim 1), whether delivery of tDCS to the front of the head is more effective than delivery to the back of the head (Aim 2), and whether tDCS delivery will alter levels of a major inhibitory neurotransmitter in the brain (GABA; Aim 3) that is important to cognitive functioning and may be disrupted in people with schizophrenia. Although this study is not intended to diagnose, cure or treat schizophrenia or any other disease, if results are positive it will encourage future large-scale studies to determine if tDCS can become an effective treatment for cognitive problems in people with schizophrenia.
- Conditions
- Schizophrenia
- Being tested
- Transcranial Direct Current Stimulation
- Keywords
- schizophrenia, EEG, tDCS, dorsolateral prefrontal cortex, cognitive control, transcranial direct current stimulation, GABA, MR spectroscopy
- Medical subject headings
- Schizophrenia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Transcranial Direct Current StimulationDevice
In tDCS, saline-soaked electrodes are temporary affixed to the scalp and connected to a battery-powered current generator. A weak (2 mA) constant current is then briefly applied (~20 minutes) to stimulate the targeted brain area (e.g. the DLPFC). To control for placebo effects, the study will utilize a sham stimulation protocol that consists of very brief constant stimulation (~1 minute). Subjects usually cannot discern the difference between the sham and experimental stimulation protocols due to habituation.
| Study group | Role | What they receive |
|---|---|---|
| DLPFC Stimulation + Task | Experimental | Intervention. 20 minutes of 2 mA direct current stimulation over the dorsolateral prefrontal cortex during cognitive task completion. Receives: Device: Transcranial Direct Current Stimulation |
| DLPFC Stimulation + Rest | Experimental | Intervention. 20 minutes of 2 mA direct current stimulation over the dorsolateral prefrontal cortex during rest. Receives: Device: Transcranial Direct Current Stimulation |
| Sham Stimulation + Task | Sham comparator | Placebo Comparator. 0.5-1 minutes of 2 mA direct current stimulation over dorsolateral prefrontal cortex followed by 19-19.5 minutes of sham stimulation, during cognitive task completion. Receives: Device: Transcranial Direct Current Stimulation |
| Sham Stimulation + Rest | Sham comparator | Placebo Comparator. 0.5-1 minutes of 2 mA direct current stimulation over dorsolateral prefrontal cortex followed by 19-19.5 minutes of sham stimulation, during rest. Receives: Device: Transcranial Direct Current Stimulation |
What is being measured
The primary outcome is the main question the study is designed to answer.
EEG Correlates of Language and Cognitive Control
Electrophysiological data recorded during completion of cognitive control tasks. We will measure oscillatory activity from 3-80 Hz.
Measured: Assessment will begin immediately following stimulation and last for about 1.5 hours.
Behavioral Response
We will assess performance on the Dot Pattern Expectancy (DPX) task (error rates).
Measured: Assessment will begin immediately following stimulation and last for about 1.5 hours.
Behavioral Response
We will assess performance on the Dot Pattern Expectancy (DPX) task (d-prime scores).
Measured: Assessment will begin immediately following stimulation and last for about 1.5 hours.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Feb 2020
- Study start9 Jan 2020
- Primary completion31 Aug 2026 (estimated)
- Study completion31 Aug 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.
- More trials run by University of California, DavisThe sponsor's other registered studies.
- 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
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 160 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of California, Davis
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04267003
- Sponsor's protocol ID
- 1515202
- Status last verified
- Mar 2026
- First submitted
- 3 Feb 2020
- Last updated
- 30 Mar 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- Yes: Select data from this study may be submitted to the National Institute of Mental Health Data Archive (NDA). NDA is a data repository run by the National Institute of Mental Health (NIMH) that allows researchers studying mental illness to collect and share de-identified information with each other. The data repository is accessible only to qualified investigators. All subject data will be de-identified (subject names will not be used) and each subject will have a separate identifier called a Global Unique Identifier (GUID) to remove any possibility that "the identities of the subjects cannot be readily ascertained or otherwise associated with the data by the repository staff or secondary data users." (45 CFR, 46.102).
Study at a glance
From the registry record, last updated by the sponsor on 30 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Transcranial Direct Current Stimulation (tDCS) Studies of Cognition, Oscillations and GABA Levels in Schizophrenia
- ClinicalTrials.gov ID
- NCT04267003
- Acronym / sponsor ID
- 1515202
- Conditions
- Schizophrenia
- Keywords
- schizophrenia, EEG, tDCS, dorsolateral prefrontal cortex, cognitive control, transcranial direct current stimulation, GABA, MR spectroscopy
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 160 participants (estimated)
- Lead sponsor
- University of California, DavisUniversity, hospital or other
- Study start
- 9 Jan 2020 (actual)
- Primary completion
- 31 Aug 2026 (estimated)
- Study completion
- 31 Aug 2026 (estimated)
- First posted
- 12 Feb 2020 (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.
People with schizophrenia often have problems with attention, learning and memory and other cognitive abilities that interfere with their work and school performance. Unfortunately, even our best treatments often do not significantly reduce these cognitive problems. The current study investigates whether or not delivering a very small electrical current to people's foreheads (called, transcranial direct current stimulation; (tDCS)) might improve functioning in the front part of the brain and reduce these cognitive problems in people with schizophrenia. tDCS is non-invasive and has been shown to improve cognitive functioning in some preliminary studies. The current study will investigate whether giving tDCS during a task is more effective than giving it during rest (Aim 1), whether delivery of tDCS to the front of the head is more effective than delivery to the back of the head (Aim 2), and whether tDCS delivery will alter levels of a major inhibitory neurotransmitter in the brain (GABA; Aim 3) that is important to cognitive functioning and may be disrupted in people with schizophrenia. Although this study is not intended to diagnose, cure or treat schizophrenia or any other disease, if results are positive it will encourage future large-scale studies to determine if tDCS can become an effective treatment for cognitive problems in people with schizophrenia.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| DLPFC Stimulation + Task | Experimental | Device: Transcranial Direct Current StimulationIntervention. 20 minutes of 2 mA direct current stimulation over the dorsolateral prefrontal cortex during cognitive task completion. |
| DLPFC Stimulation + Rest | Experimental | Device: Transcranial Direct Current StimulationIntervention. 20 minutes of 2 mA direct current stimulation over the dorsolateral prefrontal cortex during rest. |
| Sham Stimulation + Task | Sham comparator | Device: Transcranial Direct Current StimulationPlacebo Comparator. 0.5-1 minutes of 2 mA direct current stimulation over dorsolateral prefrontal cortex followed by 19-19.5 minutes of sham stimulation, during cognitive task completion. |
| Sham Stimulation + Rest | Sham comparator | Device: Transcranial Direct Current StimulationPlacebo Comparator. 0.5-1 minutes of 2 mA direct current stimulation over dorsolateral prefrontal cortex followed by 19-19.5 minutes of sham stimulation, during rest. |
Who may qualify
- Ages
- 18 to 47 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (9 listed)
- Participants must be able to sufficiently speak and understand English so as to be able to understand and complete cognitive tasks.
- All subjects must have the ability to give valid informed consent.
- Diagnosis of schizophrenia, schizophreniform or schizoaffective disorder
- No medication changes in the prior month
- No medication changes anticipated in the upcoming month
Key exclusion criteria (15 listed)
- Pacemakers
- Implanted electrical (brain and spinal) stimulators
- Implanted defibrillator
- Metallic implants
- Skin damage or skin conditions such as eczema at the sites where electrodes will be placed
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 |
|---|---|---|
| Transcranial Direct Current StimulationIn tDCS, saline-soaked electrodes are temporary affixed to the scalp and connected to a battery-powered current generator. A weak (2 mA) constant current is then briefly applied (~20 minutes) to stimulate the targeted brain area (e.g. the DLPFC). To control for placebo effects, the study will utilize a sham stimulation protocol that consists of very brief constant stimulation (~1 minute). Subjects usually cannot discern the difference between the sham and experimental stimulation protocols due to habituation. | Device | DLPFC Stimulation + Rest, DLPFC Stimulation + Task, Sham Stimulation + Rest, Sham Stimulation + Task |
Primary outcome
EEG Correlates of Language and Cognitive Control
Time frame: Assessment will begin immediately following stimulation and last for about 1.5 hours.
Electrophysiological data recorded during completion of cognitive control tasks. We will measure oscillatory activity from 3-80 Hz.
Behavioral Response
Time frame: Assessment will begin immediately following stimulation and last for about 1.5 hours.
We will assess performance on the Dot Pattern Expectancy (DPX) task (error rates).
Behavioral Response
Time frame: Assessment will begin immediately following stimulation and last for about 1.5 hours.
We will assess performance on the Dot Pattern Expectancy (DPX) task (d-prime scores).
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 30 Mar 2026.
- Learn more or sign up for the study here!Link provided by the sponsor.
- Individual participant dataSharing planned: Yes. Select data from this study may be submitted to the National Institute of Mental Health Data Archive (NDA). NDA is a data repository run by the National Institute of Mental Health (NIMH) that allows researchers studying mental illness to collect and share de-identified information with each other. The data repository is accessible only to qualified investigators. All subject data will be de-identified (subject names will not be used) and each subject will have a separate identifier called a Global Unique Identifier (GUID) to remove any possibility that "the identities of the subjects cannot be readily ascertained or otherwise associated with the data by the repository staff or secondary data users." (45 CFR, 46.102).
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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.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Transcranial Direct Current Stimulation in people with Schizophrenia, run by University of California, Davis at 1 site in United States.
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 9 inclusion and 15 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: looking for participants now, as of the sponsor's last update on 30 Mar 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 United States. 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. 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 Molly A Bainbridge ((916) 734-8779, mebainbridge@ucdavis.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
EEG Correlates of Language and Cognitive Control (time frame: Assessment will begin immediately following stimulation and last for about 1.5 hours.). 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?
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 30 Mar 2026.