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
Article Date: 2018-08-09 (Revised: 2018-08-14)
Authors: Chang CC, Tzeng NS, Chao CY, Yeh CB, Chang HA
PMID Link: 30107404
Title: The international journal of neuropsychopharmacology
Abbreviation: Int. J. Neuropsychopharmacol.
Citation: Int. J. Neuropsychopharmacol. 2018 Aug;
Background: 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, but the results are mixed. Fronto-temporal tDCS 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 tDCS on the severity of AVHs, other schizophrenia symptoms and insight in a large double blind, randomized, sham-controlled trial.
Methods: Sixty patients with medication-refractory AVHs were randomized over two conditions: tDCS with 2-mA, twice-daily sessions for five 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 tDCS failed to cause significant changes in the severity of AVHs and other schizophrenia symptoms. The levels of insight into illness (effect size = 0.511, p < 0.001) and positive symptoms (effect size = 0.781, p < 0.001) were largely promoted by 5 days of tDCS relative to sham treatment. The beneficial effects on the two insight dimensions remained one month after tDCS.
Conclusions: Fronto-temporal tDCS is not more effective for AVHs and other schizophrenia symptoms than sham treatment. But the results of tDCS-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.