dACC-Targeted Temporal Interference for Negative and Cognitive Symptoms in Schizophrenia

Inclusion Criteria: * All of the following criteria must be satisfied for enrolment: 1. A confirmed diagnosis of schizophrenia established according to the criteria set forth in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5); 2. Age between 18 and 65 years, regardless of sex, with completion of at least junior secondary education and the capacity to undergo neurocognitive testing; 3. Clinically meaningful negative symptoms, operationalized as a PANSS negative symptom subscale (PANSS-NS) total score ≥ 20 with a rating of ≥ 3 on a minimum of one individual PANSS-NS item ; the PANSS positive symptom subscale score must additionally not exceed 19; 4. Objective cognitive impairment evidenced by an age- and sex-adjusted composite z-score of ≤ -1.0 on the Chinese version of the Brief Assessment of Cognition in Schizophrenia (BACS), reflecting performance at least one standard deviation below normative values derived from Mandarin-speaking populations; 5. Maintenance on an unchanged antipsychotic regimen - with no modification to medication type or dose - for at least 30 days prior to informed consent and continuing throughout the trial; 6. Voluntary agreement to participate, documented by written informed consent following thorough explanation of study objectives and procedures; where applicable, a legally authorized representative may provide or co-sign consent. Exclusion Criteria: * Individuals will be ineligible if any of the following conditions apply: 1. A concurrent psychiatric diagnosis requiring active clinical management, including but not limited to major depressive episode or bipolar disorder, or the presence of a comorbid neurological disorder or serious physical illness; 2. Current or past substance use disorder, encompassing problematic consumption of alcohol or illicit substances; 3. A documented seizure disorder or marked electroencephalographic abnormalities, particularly epileptiform activity; 4. Evidence of structural brain pathology, including organic lesions, prior traumatic brain injury, or previous neurosurgical intervention; 5. Presence of ferromagnetic implants or any other contraindication to MRI or tTIS exposure, including intracranial metallic clips, implanted cardiac devices, or cochlear implants; 6. Current use of glucocorticoids or other pharmacological agents known to meaningfully alter cortical excitability; 7. Prior exposure to any neuromodulatory intervention - including modified electroconvulsive therapy (MECT), repetitive transcranial magnetic stimulation (TMS), or transcranial direct current stimulation (tDCS) - within the 30 days preceding enrolment.