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NCT Number: NCT04267003

Effects of Brain Stimulation on 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.

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Key information

Conditions

Schizophrenia Mental Disorders Schizophrenia Spectrum and Other Psychotic Disorders

Age range

18 year–47 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Imaging Research Center

Sacramento, California, 95817, United States

Location status: Recruiting

Location contact

Cameron Carter, M.D.

PRINCIPAL_INVESTIGATOR

Molly Bainbridge

CONTACT

[email protected]

916-734-3749

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 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.

Inclusion criteria

for Patients with Schizophrenia Only:

  • 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

Exclusion criteria

  • 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

Treatment and study plan

Transcranial Direct Current Stimulation

Device

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.

Primary outcomes

  1. 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.

  2. 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).

  3. 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).

Study contacts

Contact information is provided by the study sponsor or research team.

Molly A Bainbridge

CONTACT

[email protected]

(916) 734-8779

Sponsors and collaborators

Lead sponsor

University of California, Davis

Other

Registry information

Official study title

Transcranial Direct Current Stimulation (tDCS) Studies of Cognition, Oscillations and GABA Levels in Schizophrenia

Important dates

Study start
2020
Primary completion
2026
Study completion
2026
First posted
Feb 12, 2020
Registry last updated
Mar 30, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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