The Effects of Add-on Fronto-Temporal Transcranial Direct Current Stimulation (tDCS) on Auditory Verbal Hallucinations, Other Psychopathological Symptoms, and Insight in Schizophrenia: A Randomized, Double-Blind, Sham-Controlled Trial

摘要

Background The efficacy of fronto-temporal transcranial direct current stimulation in treating auditory verbal hallucinations and other psychopathological symptoms of schizophrenia patients has been examined in a small number of clinical trials with limited sample sizes, but the results are mixed. Fronto-temporal transcranial direct current stimulation has also been demonstrated to enhance patients’ insight into their mental illness in an open-label pilot study. The current investigation aimed to investigate the therapeutic effects of fronto-temporal transcranial direct current stimulation on the severity of auditory verbal hallucinations, other schizophrenia symptoms, and insight in a large double blind, randomized, sham-controlled trial. Methods Sixty patients with medication-refractory auditory verbal hallucinations were randomized over 2 conditions: transcranial direct current stimulation with 2-mA, twice-daily sessions for 5 consecutive days, with anodal stimulation to the left prefrontal cortex and cathodal stimulation to the left temporo-parietal junction, and sham treatment. Results Fronto-temporal transcranial direct current stimulation failed to cause significant changes in the severity of auditory verbal hallucinations and other schizophrenia symptoms. The levels of insight into illness (effect size=0.511, P .001) and positive symptoms (effect size=0.781, P .001) were largely promoted by 5 days of transcranial direct current stimulation relative to sham treatment. The beneficial effects on the 2 insight dimensions remained 1 month after transcranial direct current stimulation. Conclusions Fronto-temporal transcranial direct current stimulation is not more effective for auditory verbal hallucinations and other schizophrenia symptoms than sham treatment. But the results of transcranial direct current stimulation-associated improvement in awareness of illness and positive symptoms show promise and provide a new direction for future research into insight promotion interventions in schizophrenia. schizophrenia , transcranial direct current stimulation , fronto-temporal montage , auditory verbal hallucination , insight Significance Statement The efficacy of fronto-temporal transcranial direct current stimulation (tDCS) in treating auditory verbal hallucinations (AVHs) and other psychopathological symptoms of schizophrenia patients has been examined in a small number of clinical trials with limited sample sizes. Fronto-temporal tDCS has also been demonstrated to enhance patients’ insight into their mental illness in an open-label pilot study. We hypothesized that fronto-temporal tDCS may not only improve AVHs and other psychotic symptoms but also intensify insight in schizophrenia. Our main findings indicated that tDCS did not reduce AVHs and other psychopathological symptoms. After treatment with tDCS, however, patients’ insight into illness and positive symptoms rapidly heightened. The beneficial effect of tDCS on insight lasted for at least 1 month. These observations suggest that fronto-temporal tDCS is not effective for AVHs and other schizophrenia symptoms, but its effect on insight levels provides a new direction for future research into insight promotion interventions in schizophrenia.