Effects of Brain Stimulation on Cognition, Oscillations and GABA Levels in Schizophrenia
Transcranial Direct Current Stimulation (tDCS) Studies of Cognition, Oscillations and GABA Levels in Schizophrenia
1 other identifier
interventional
160
1 country
1
Brief 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. 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.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P75+ for not_applicable schizophrenia
Started Jan 2020
Longer than P75 for not_applicable schizophrenia
1 active site
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
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Study Timeline
Key milestones and dates
Study Start
First participant enrolled
January 9, 2020
CompletedFirst Submitted
Initial submission to the registry
February 3, 2020
CompletedFirst Posted
Study publicly available on registry
February 12, 2020
CompletedPrimary Completion
Last participant's last visit for primary outcome
August 31, 2026
ExpectedStudy Completion
Last participant's last visit for all outcomes
August 31, 2026
March 30, 2026
March 1, 2026
6.6 years
February 3, 2020
March 26, 2026
Conditions
Keywords
Outcome Measures
Primary Outcomes (3)
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.
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).
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).
Assessment will begin immediately following stimulation and last for about 1.5 hours.
Study Arms (4)
DLPFC Stimulation + Task
EXPERIMENTALIntervention. 20 minutes of 2 mA direct current stimulation over the dorsolateral prefrontal cortex during cognitive task completion.
DLPFC Stimulation + Rest
EXPERIMENTALIntervention. 20 minutes of 2 mA direct current stimulation over the dorsolateral prefrontal cortex during rest.
Sham Stimulation + Task
SHAM COMPARATORPlacebo 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 COMPARATORPlacebo 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.
Interventions
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.
Eligibility Criteria
You may qualify if:
- 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
- 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
You may not qualify if:
- 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
- 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
Contact the study team to confirm eligibility.
Sponsors & Collaborators
Study Sites (1)
Imaging Research Center
Sacramento, California, 95817, United States
Related Links
MeSH Terms
Conditions
Interventions
Condition Hierarchy (Ancestors)
Intervention Hierarchy (Ancestors)
Central Study Contacts
Study Design
- Study Type
- interventional
- Phase
- not applicable
- Allocation
- RANDOMIZED
- Masking
- DOUBLE
- Who Masked
- PARTICIPANT, INVESTIGATOR
- Purpose
- BASIC SCIENCE
- Intervention Model
- CROSSOVER
- Sponsor Type
- OTHER
- Responsible Party
- SPONSOR
Study Record Dates
First Submitted
February 3, 2020
First Posted
February 12, 2020
Study Start
January 9, 2020
Primary Completion (Estimated)
August 31, 2026
Study Completion (Estimated)
August 31, 2026
Last Updated
March 30, 2026
Record last verified: 2026-03
Data Sharing
- IPD Sharing
- Will share
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).