Adjunctive multi-session transcranial direct current stimulation for neurocognitive dysfunction in schizophrenia: A meta-analysis

Findings of multi-session transcranial direct current stimulation (tDCS) as an adjunctive treatment of neurocognitive dysfunction in schizophrenia have been inconsistent. This meta-analysis of randomized controlled trials (RCTs) investigated the neurocognitive effects of adjunctive multi-session tDCS for schizophrenia. Twelve RCTs covering 418 schizophrenia patients were included and analyzed in this meta-analysis. The RevMan software (Version 5.3) was used to calculate risk ratios (RRs) and standardized mean differences (SMDs) with their 95% confidence intervals (CIs). Adjunctive tDCS outperformed the comparator in improving working memory deficits (SMD = 0.34, 95% CI: 0.03, 0.65; I² = 52%; p = 0.03), but no significant effects were found in other cognitive domains. No group differences were found with regard to total psychopathology measured by the Brief Psychiatric Rating Scale and the Positive and Negative Symptom Scale (SMD =−0.29, 95%CI: −0.61, 0.03; I² = 50%, p = 0.07) and discontinuation due to any reason (RR=0.80, 95%CI: 0.39, 1.66; I² = 9%, p = 0.56). Adjunctive tDCS appears to have a significant therapeutic effect improving the working memory deficits in schizophrenia.