Efficacy and Safety of tACS vs tDCS in Schizophrenia

Comparison of Efficacy and Safety of Transcranial Alternating Current Stimulation vs Transcranial Direct Current Stimulation on Psychopathology Measures and Neurocognition in Chronic Schizophrenia: A Randomized Double-blind Controlled Trial

This clinical trial aims to compare the efficacy and safety of transcranial Alternating current stimulation (tACS) vs. transcranial Direct current stimulation (tDCS) vs. sham stimulation in chronic schizophrenia.

The main question it aims to answer is:

• In comparison to tDCS, can tACS improve the clinical outcome of patients with chronic schizophrenia?

Participants will be randomised into 3 groups receiving either tDCS, tACS or sham stimulation and changes in psychopathology and neuro-cognition with the interventions will be compared within and between the groups. The primary outcome measure is the Positive and Negative Syndrome Scale (PANSS), while secondary outcome measures are the Auditory Hallucination Rating Scale (AHRS), Brief Cognitive Assessment Tool for Schizophrenia (B-CATS), and Global Assessment of Functioning (GAF).

The proposed double-blind RCT will be conducted over 3 years involving 2 centres among patients with chronic schizophrenia (moderate-severe symptoms) of either gender, aged between 18 and 60. Those with any psychiatric emergency or contraindications for tDCS will be excluded. At baseline, PANSS will be administered to assess the severity of symptom dimension, AHRS for auditory hallucinations, B-CATS for neurocognitive deficits and GAF for global functionality. Patients will be randomized equally to 3 treatment groups: tACS, tDCS, or sham stimulation (30 in each group). The intervention will involve Cathodal stimulation of left TPJ and Anodal stimulation of left DLPFC. The transcranial brain stimulations: tACS, tDCS, or sham stimulation, will be given 2 sessions per day for 10 days. Following the 5th day and after the last treatment session, PANSS, AHRS, B-CATS, and GAF will be readministered to observe for the changes in the various outcome parameters. Any new treatment-emergent serious adverse effect will be recorded.

Inclusion Criteria:

1. Diagnosis of Schizophrenia as per ICD-10 DCR for more than 2 years
2. Moderate-severe symptoms (PANSS score > 75 and/or CGI-SCH score>4) [24]
3. On stable dosing of antipsychotic medications (no changes in medication or doses for 1 month prior to enrolment)
4. Both sexes; Age range: 18-60 years
5. Right-handed
6. Written informed consent by the patient

Exclusion Criteria:

1. Features suggestive of psychiatric emergency (for example: suicidal risk, catatonia, prolonged nutritional deprivation) or others (for example: aggression or excitement)
2. Any contraindication to tDCS procedure: Metal in the head, Implanted brain medical devices, Local lesion or injury in the scalp / head
3. Co-morbid neurological disease
4. Left Handed