tACS for Working Memory in Schizophrenia

NCT07701343 | Recruiting

• 1 other identifier: LYG20260081
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

This study is a randomized, single-blind, sham-controlled crossover trial enrolling 30 schizophrenia patients, each receiving one active and one sham tACS session (7-day washout), targeting P3/P4 at individual alpha frequency (2mA, 30min) during a working memory task, with accuracy and reaction time as primary outcomes, alongside EEG and neurophysiological measures, to test the efficacy and mechanisms of individualized alpha-tACS on working memory.

Conditions

Schizophrenia; Working Memory

Keywords

Schizophrenia; Working Memory; Transcranial Alternating Current Stimulation

Outcome Measures

Primary Outcomes (2)

• Working Memory Accuracy

  Assessment of task accuracy on the Sternberg Item Recognition Paradigm (SIRP). Participants are required to judge whether a probe stimulus belongs to a previously memorized set, with memory set sizes of 1 and 5. The outcome is measured as the percentage of correct responses (0-100%) across all trials, with higher scores indicating better working memory performance.

  Day 1 (baseline, prior to first intervention); within 15 minutes after Session 1; Day 9 (prior to second intervention, after 7-day washout); within 15 minutes after Session 2.

• Working Memory Reaction Time

  Assessment of response speed on the Sternberg Item Recognition Paradigm (SIRP). Participants are required to judge whether a probe stimulus belongs to a previously memorized set, with memory set sizes of 1 and 5. The outcome is measured as the mean response latency for correct responses only, calculated from stimulus onset to the participant's button press, with shorter times indicating faster processing speed.

  Day 1 (baseline, prior to first intervention); within 15 minutes after Session 1; Day 9 (prior to second intervention, after 7-day washout); within 15 minutes after Session 2.

Secondary Outcomes (10)

• Changes in MCCB Performance

  Baseline, on the day after each of the two interventions

• Changes in Positive and Negative Symptom Scale (PANSS) Scores

  Before and one week after each of the two interventions.

• Changes in Scale for the Assessment of Negative Symptoms (SANS) Scores

  Before and one week after each of the two interventions.

• Changes in Calgary Depression Scale for Schizophrenia (CDSS) Scores

  Before and one week after each of the two interventions.

• Changes in Brain Function

  Baseline, on the day after each of the two interventions.

Study Arms (2)

sham group

SHAM COMPARATOR

sham stimulation

Device: sham stimulation

active group

EXPERIMENTAL

transcranial alternating current stimulation

Device: transcranial alternating current stimulation

Interventions

transcranial alternating current stimulation DEVICE

For montage 1, active electrode at P3 (10-10 system), return electrodes at P1, P5, PO3, CP3. For montage 2, active electrode at P4, return electrodes at P2, P6, PO4, CP4. Conductive paste ensures impedance \<10 kΩ. Individual alpha frequency is used, calculated before each session from mean EEG at P3/P4 during SIRP task. Stimulation intensity is 2 mA (peak-to-zero) via electric field modeling. Stimulation is delivered during SIRP task, 30 min total per session (including 15s ramp-up/down), with continuous sine wave output.

active group

sham stimulation DEVICE

Sham stimulation provides only a 15-second ramp-up and ramp-down current at the beginning and end of each session to mimic the initial tingling or itching sensation on the scalp produced by real stimulation, but delivers no effective stimulation current during the main phase of the task period.

sham group

Eligibility Criteria

• Age: 18 Years - 50 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Aged 18-50 years, meeting the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnostic criteria for schizophrenia, confirmed by the Structured Clinical Interview for DSM-5 (SCID-5).
• Spatial span T-score \<40 on the MATRICS Consensus Cognitive Battery (MCCB).
• Taking 1-2 antipsychotic medications, with stable dosage for at least 1 week prior to enrollment. No use of mood stabilizers, antidepressants, or excessive benzodiazepines (lorazepam equivalent \>2 mg/day). The type and dosage of antipsychotic medications remain unchanged during the treatment period.
• Impaired functioning in daily activities.
• Willing to participate in this study and provide written informed consent.

You may not qualify if:

• Previously diagnosed with or comorbid any other DSM-5 mental disorder besides schizophrenia.
• Presence of significant mood symptoms or substance use disorder (other than caffeine and/or tobacco).
• Presence of any contraindication to transcranial alternating current stimulation (tACS).
• Received other forms of electrical or magnetic stimulation therapy within 1 month prior to enrollment.
• History or current presence of any major physical illness, neurological disorder, or traumatic brain injury that may affect brain structure or function.
• Pregnant or breastfeeding women, or women planning to become pregnant during the study period.

Sponsors & Collaborators

• Central South University: lead

Study Sites (1)

The Second Xiangya Hospital of Central South University

Changsha, Hunan, 410011, China

RECRUITING

MeSH Terms

Conditions

Schizophrenia

Interventions

Transcranial Direct Current Stimulation

Condition Hierarchy (Ancestors)

Schizophrenia Spectrum and Other Psychotic Disorders; Mental Disorders

Intervention Hierarchy (Ancestors)

Electric Stimulation Therapy; Therapeutics; Convulsive Therapy; Psychiatric Somatic Therapies; Behavioral Disciplines and Activities; Electroshock; Psychological Techniques

Central Study Contacts

Renrong Wu

CONTACT

15874179855; wurenrong@csu.edu.cn

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Masking Details: This study used a single-blind design, with participants blinded to treatment allocation (active vs. sham). The device operator was not blinded due to differing parameter settings between active and sham stimulation, but was not involved in recruitment, clinical assessment, or data analysis. To maintain blinding integrity, participants were prohibited from discussing treatment-related sensations with the operator or among themselves. The sham procedure mimicked the initial scalp sensation of active stimulation to enhance blinding credibility.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Study Record Dates

• First Submitted: July 2, 2026
• First Posted: July 14, 2026
• Study Start: July 6, 2026
• Primary Completion (Estimated): October 31, 2026
• Study Completion (Estimated): December 31, 2026
• Last Updated: July 14, 2026

Record last verified: 2026-07

Data Sharing

• IPD Sharing: Will not share

Locations

CN (1)