Efficacy of Transcranial Alternating Current Stimulation (tACS) for Treating Hallucinations: A Systematic Review and...

Area of Science:

• Neuroscience
• Psychiatry
• Medical Technology

Background:

• Persistent auditory hallucinations are a significant challenge in psychiatric disorders, particularly schizophrenia.
• Non-invasive brain stimulation techniques like TMS and tDCS have shown some efficacy for auditory hallucinations.
• The effectiveness of transcranial alternating current stimulation (tACS) for hallucinations requires systematic review.

Purpose of the Study:

• To systematically evaluate the efficacy of tACS in reducing hallucinations in psychiatric populations.
• To synthesize findings from randomized controlled trials (RCTs) and other study designs using meta-analysis and qualitative synthesis.

Main Methods:

• Systematic literature search across PubMed, Scopus, EMBASE, and clinical trial registries.
• Inclusion of adult psychiatric populations with measured hallucinations using standardized scales.
• Meta-analysis of three RCTs and qualitative synthesis of five additional studies; risk of bias and certainty of evidence assessed.

Main Results:

• Meta-analysis of three RCTs (72 participants) revealed no significant difference between tACS and sham treatment for hallucination reduction.
• Qualitative synthesis indicated potential benefits of gamma-frequency (40 Hz) tACS for auditory hallucinations.
• Reported side effects were mild and infrequent; overall risk of bias was moderate to high, with low certainty of evidence.

Conclusions:

• Current evidence suggests tACS is not significantly effective for reducing hallucinations in psychiatric disorders.
• Gamma-frequency tACS warrants further investigation for auditory hallucinations, but findings are inconclusive.
• Larger, high-quality trials are necessary to establish the definitive efficacy and safety of tACS for psychiatric hallucinations.