tACS for Self-Other Boundary in Schizophrenia

NCT07818668 | Recruiting DMC

• 1 other identifier: 81250874
• Study Type: interventional
• Target: 100
• Locations: 1 country
• Sites: 1

Brief Summary

This clinical trial investigates whether a non-invasive brain stimulation technique called transcranial alternating current stimulation (tACS) can improve the ability to distinguish between "self" and "others" in patients with schizophrenia. The intervention targets the medial prefrontal cortex (mPFC), a brain region critical for self-awareness, using 10Hz stimulation at 2mA for 20 minutes daily over five consecutive days. The study has two main objectives. First, it aims to characterize the underlying mechanisms of self-other boundary dysfunction in schizophrenia by comparing behavioral and brain activity patterns among three participant groups: patients with schizophrenia, individuals with high schizotypal traits, and healthy volunteers. During this mechanism phase, participants perform two computer-based self-other face recognition tasks designed to manipulate prior probability (varying the proportion of self vs. other faces across blocks) and perceptual uncertainty (adjusting the Gaussian blur level of face images), while their brain activity is recorded via EEG. Behavioral performance (response time, accuracy, and sensitivity d') and EEG markers (alpha-band power, N170, and P1 components) are analyzed to quantify deficits in predictive coding. Second, the study aims to evaluate the therapeutic efficacy of tACS in a randomized, double-blind, sham-controlled trial. The primary hypothesis is that active tACS, compared to sham stimulation, will significantly improve patients' accuracy in distinguishing self from other faces, accompanied by enhanced alpha-band brain oscillations and reduced scores on the Examination of Anomalous Self-Experience (EASE) scale. All participants will undergo clinical assessments, complete the face recognition tasks while their brain activity is monitored via EEG, and complete follow-up assessments 48 hours after the last stimulation session. The findings from this study may provide a novel, mechanism-based non-pharmacological intervention for addressing core self-disturbance in schizophrenia, potentially improving patients' social functioning and quality of life.

Conditions

Schizophrenia / Schizoaffective Disorder

Outcome Measures

Primary Outcomes (2)

• Change in Self-Other Face Recognition Sensitivity (d')

  Change from baseline in the sensitivity index (d') measured by the self-other face recognition task at 48 hours after the last tACS session. Participants distinguish between self and other faces under varying prior probability and perceptual uncertainty conditions. The sensitivity index (d') is dimensionless; a higher value indicates better ability to differentiate between self and other faces.

  Baseline (pre-intervention) and 48 hours after the last tACS session

• Change in Medial Prefrontal Cortex Alpha-Band Oscillatory Power

  Change from baseline in alpha-band (8-13 Hz) oscillatory power measured by electroencephalography (EEG) over the medial prefrontal cortex (mPFC) at 48 hours after the last tACS session. Alpha-band power is assessed during resting-state and self-other face recognition task performance to evaluate the neural effects of the intervention.

  Baseline (pre-intervention) and 48 hours after the last tACS session

Study Arms (2)

Active tACS Group

ACTIVE COMPARATOR

Participants receive 10Hz transcranial alternating current stimulation (tACS) at 2mA intensity, targeting the medial prefrontal cortex (mPFC), for 20 minutes per day over 5 consecutive days.

Device: Transcranial Alternating Current Stimulation (tACS)

Sham tACS Group

SHAM COMPARATOR

Participants receive sham stimulation with identical electrode placement and procedures as the active group, but current is delivered only during the 30-second ramp-up and ramp-down periods, with no active stimulation for the remainder of the 20-minute session.

Device: Sham Transcranial Alternating Current Stimulation (tACS)

Interventions

Transcranial Alternating Current Stimulation (tACS) DEVICE

10Hz tACS with 2mA intensity, 20 minutes per day

Active tACS Group

Sham Transcranial Alternating Current Stimulation (tACS) DEVICE

Sham stimulation with identical electrode placement and procedures as the active tACS group. Current is delivered only during the 30-second ramp-up and ramp-down periods, with no active stimulation for the remainder of the 20-minute session.

Sham tACS Group

Eligibility Criteria

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

You may qualify if:

• Diagnosis of schizophrenia according to DSM-5 criteria
• Presence of hallucinations or delusions
• Age between 18 and 50 years
• Clinically stable on a stable dose of antipsychotic medication for at least 4 weeks prior to enrollment, with no anticipated medication changes during the study period
• Normal or corrected-to-normal vision (≥ 20/40) as assessed by standard visual acuity test
• Able to understand and provide written informed consent

You may not qualify if:

• History of neurological disorders (e.g., epilepsy, stroke, traumatic brain injury)
• Presence of other major psychiatric disorders (e.g., bipolar disorder, major depressive disorder)
• Previous receipt of non-invasive brain stimulation (e.g., tACS, tDCS, rTMS)
• History of substance dependence or abuse within the past 6 months
• Metal implants in the head or skull (e.g., cochlear implants, deep brain stimulators)
• Pregnancy or breastfeeding
• Presence of skin lesions, wounds, or sensitive skin at electrode placement sites (Fpz, AF7, AF8, F5, F6)

Sponsors & Collaborators

• Chunyan Zhu: lead

Study Sites (1)

The Fourth People's Hospital of Hefei

Hefei, Anhui, China

RECRUITING

MeSH Terms

Conditions

Schizophrenia; Psychotic Disorders

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

long chen

CONTACT

18712333621; chen37213@163.com

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: The dean of the School of Mental Health and Psychological Sciences at Anhui Medical University

Study Record Dates

• First Submitted: August 13, 2026
• First Posted: September 14, 2026
• Study Start: March 17, 2026
• Primary Completion (Estimated): September 15, 2027
• Study Completion (Estimated): September 30, 2027
• Last Updated: September 17, 2026

Record last verified: 2026-09

Locations

CN (1)