Cognitive Effects of tDCS and tRNS in Schizophrenia

March 15, 2026 updated by: Mohammad Ali Salehinejad, The National Brain Mapping Laboratory (NBML)

Cognitive Effects of Transcranial Direct Current Stimulation (tDCS) and Transcranial Random Noise Stimulation (tRNS) in Schizophrenia: A Random, Crossover Study

The purpose of this study is to investigate the cognitive effects of different electrical stimulation modalities, such as transcranial direct and random-noise stimulation over the dorsolateral prefrontal cortex, in schizophrenia.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

36

Phase

  • Not Applicable

Contacts and Locations

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

Study Locations

  • Iran
      • Tehran, Iran
        • Payame Noor University, Tehran Branch
      • Zanjān, Iran
        • Zanjan University

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

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Diagnosis of schizophrenia based on Diagnostic and Statistical Manual (DSM)5
  • Being 18-50 years old (male and female)
  • If female, negative urine pregnancy test
  • feasibility for tDCS/tRNS interventions according to safety guidelines
  • stable medication regime, especially for classical neuroleptics and all central nervous system activating medications, if taken, 4-6 weeks before the experiment
  • fluency in the native language
  • right-handed
  • Required written informed consent signed by patients' guardian

Exclusion Criteria:

  • pregnancy
  • alcohol or substance dependence
  • comorbid bipolar disorder and mood disorder
  • history of seizure
  • history of neurological disorder
  • history of head injury
  • Presence of ferromagnetic objects in the body that are contraindicated for brain stimulation of the head (pacemakers or other implanted electrical devices, brain stimulators, some types of dental implants, aneurysm clips, metallic prostheses, permanent eyeliner, implanted delivery pump, or shrapnel fragments)

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: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: tDCS group
In tDCS, direct electrical currents at the intensity of 2 mA are generated by an electrical stimulator and are noninvasively delivered to the left and right dorsolateral prefrontal cortex through a pair of saline-soaked sponge electrodes (7×5 cm) for 30 minutes.
Device: transcranial direct current stimulation (tDCS) active stimulator
In tDCS the electrical current is applied directly between electrodes mounted on the head which can can de-or hyperpolarizes resting membrane potential and thereby modulate cortical excitability
Active Comparator: tRNS group
In tRNS, direct electrical currents at the intensity of 2 mA amplitude (offset at 1 mA) and frequency of 100-640 Hz are generated by an electrical stimulator and are noninvasively delivered to the left and right dorsolateral prefrontal cortex through a pair of saline-soaked sponge electrodes (7×5 cm) for 30 minutes.
Device: transcranial random noise stimulation (tRNS)
Here, an alternating electrical current is applied at a mix of frequencies it is called transcranial random noise stimulation (tRNS), which can be delivered in low (between 0.1-100 Hz) or high (between 101-640 Hz) frequency stimulation
Sham Comparator: sham group
In sham group, placebo stimulation is generated by an electrical stimulator and is noninvasively delivered to the left and right dorsolateral prefrontal cortex through a pair of saline-soaked sponge electrodes (7×5 cm) for 30 minutes.
Device: transcranial direct current stimulation (tDCS) sham stimulator
Here a sham electrical current is applied directly between electrodes mounted on the head which can can de-or hyperpolarizes resting membrane potential and thereby modulate cortical excitability

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Spatial Working Memory behavioral performance
Time Frame: During procedure (4 minutes)
The test begins with a number of coloured squares (boxes) shown on the screen. The aim of this test is that by selecting the boxes and using a process of elimination, the participant should find one yellow 'token' in each of a number of boxes and use them to fill up an empty column on the right-hand side of the screen.
During procedure (4 minutes)
executive function behavioral performance
Time Frame: During procedure (8-10 minutes)
The participant is shown two displays containing three coloured balls. The test administrator first demonstrates to the participant how to move the balls in the lower display to copy the pattern in the upper display and completes one demonstration problem, where the solution requires one move. The participant must then complete three further problems, one each requiring two moves, three moves, and four moves. Next, the participant is shown further problems and must work out in their head how many moves the solutions require and then select the appropriate box at the bottom of the screen to indicate their response
During procedure (8-10 minutes)
The Positive and Negative Affect Schedule (PANAS)
Time Frame: through study completion, an average of 3 weeks
The Positive and Negative Affect Schedule (PANAS) is a self-report questionnaire that consists of two 10-item scales to measure both positive and negative affect. Each item is rated on a 5-point scale of 1 (not at all) to 5 (very much).
through study completion, an average of 3 weeks

Collaborators and Investigators

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

Sponsor

The National Brain Mapping Laboratory (NBML)

Collaborators

RWTH Aachen University
Leibniz Research Centre for Working Environment and Human Factors
Payame Noor University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

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)

January 1, 2023

Primary Completion (Actual)

November 1, 2023

Study Completion (Actual)

July 22, 2024

Study Registration Dates

First Submitted

November 24, 2023

First Submitted That Met QC Criteria

December 2, 2023

First Posted (Actual)

December 4, 2023

Study Record Updates

Last Update Posted (Actual)

March 18, 2026

Last Update Submitted That Met QC Criteria

March 15, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • ifado-PNU

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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