Therapeutic efficacy of transcranial direct current stimulation in treating auditory hallucinations in schizophrenia: A meta-analysis

BACKGROUND Schizophrenia is a chronic psychiatric condition with complex symptomatology, including debilitating auditory hallucinations. Transcranial direct current stimulation (tDCS) has been explored as an adjunctive treatment to alleviate such symptoms. AIM To evaluate the therapeutic efficacy of tDCS in schizophrenia. METHODS Adhering to PRISMA guidelines, we systematically searched PubMed, Embase, Web of Science, and the Cochrane Library on September 19, 2023, for randomized controlled trials examining the efficacy of tDCS in schizophrenia, with no language or time restrictions. We included studies that compared tDCS with a control condition and reported clinically relevant outcomes. Data extraction and quality assessments were performed by independent evaluators using the Cochrane Collaboration's risk of bias tool. Statistical heterogeneity was evaluated, and a random-effects model was applied due to moderate heterogeneity (I2 = 41.3%). RESULTS Nine studies comprising 425 participants (tDCS group: 219, control group: 206) were included. The meta-analysis demonstrated a significant reduction in auditory hallucination scores following tDCS treatment (weighted mean difference: -2.18, 95% confidence interval: -4.0 to -0.29, P < 0.01). Sensitivity analysis confirmed the robustness of the results, with no significant influence from individual studies. Additionally, publication bias was not detected, supporting the reliability and generalizability of the findings. These results underscore the efficacy of tDCS as a therapeutic intervention for auditory hallucinations in schizophrenia. CONCLUSION tDCS significantly reduces auditory hallucinations in schizophrenia, suggesting its potential as an effective adjunctive treatment for managing this disabling symptom. The findings highlight the practical significance of tDCS in clinical settings, particularly for patients with treatment-resistant auditory hallucinations.