In a systematic review and meta-analysis published in Schizophrenia Research, transcranial direct current stimulation (tDCS) was shown to reduce auditory hallucinations among patients with schizophrenia.
Korean researchers identified 106 participants with schizophrenia from 3 sham-controlled and 3 open-label trials that assessed the impact of tDCS on auditory hallucinations. Auditory hallucination outcomes were assessed in these studies using the Positive and Negative Syndrome Scale, Auditory Hallucination Rating Scale, or the Auditory Hallucination Subscale of the Psychotic Symptom Rating Scales.
The combined effect size of tDCS on auditory hallucination outcomes was high (Hedges’ g 0.919; 95% CI, 0.636-1.202). The effect of tDCS demonstrated heterogeneity across studies based on the Higgin’s I2 test (I2 67.9%; P =.008).
In meta-regression analyses with 1000 permutations, the investigators evaluated the impact of age, gender, education year, and IQ on treatment response. Only age was associated with heterogeneity (P =.09). However, they noted that the small sample size and lack of details reported in the studies may limit the ability to determine whether other factors affect treatment response.
The study authors concluded that “these findings suggest that tDCS with an anode and a cathode would be useful in the treatment of schizophrenia patients suffering from auditory hallucinations.”
Lee TY, Lee J, Kim M, Kwon JS. The effect of transcranial direct current stimulation on auditory hallucination in patients with schizophrenia [published online June 15, 2017]. Schizophr Res. doi:10.1016/j.schres.2017.06.012