Abstract
Cognitive deficits are a core and disabling feature of psychotic disorders, specifically schizophrenia. Current treatments for impaired cognition in schizophrenia remain insufficient. Recent research suggests transcranial direct current stimulation (tDCS) targeting the dorsolateral prefrontal cortex can potentiate cognitive improvements in healthy individuals and those with psychiatric conditions, such as schizophrenia. However, this burgeoning literature has not been quantitatively evaluated. Through a literature search and quantitative review, we identified 194 papers on tDCS, psychosis, and cognition. Selection criteria included pre/post design and sham control to achieve specific sham-adjusted effect sizes. The 6 retained studies all address schizophrenia populations and include single and repeated stimulation, as well as within and between subject designs. Small positive effects were found for anodal stimulation on behavioral measures of attention and working memory, with tentative findings for cognitive ability and memory. Cathodal stimulation yielded a small positive effect on behaviorally measured cognitive ability. Neurophysiological measures of attention showed a small to medium down-modulation effect for anodal stimulation. Implications of these findings and guidelines for future research are discussed. As revealed by this report, due to the paucity of data available, much remains unknown regarding the clinical efficacy of tDCS in schizophrenia.
Highlights
Impaired cognition is a significant and disabling feature of psychotic disorders such as schizophrenia
This report captures the current state of the literature as it pertains to the cognitive outcomes from transcranial direct current stimulation (tDCS) targeted at the dorsolateral prefrontal cortex (DLPFC) in schizophrenia
None of the effects observed in this small sample rule-out the possibility of null effects, we were able to quantitatively summarize current knowledge and provide the central tendency of the effects on cognitive outcomes following tDCS over the DLPFC
Summary
Impaired cognition is a significant and disabling feature of psychotic disorders such as schizophrenia. Transcranial current stimulation (tCS) is a non-invasive neuromodulation technique that uses small, directed electrical currents to alter cortical brain activity (Nitsche and Paulus, 2001). Research has indicated contradictory effects of stimulation in some patient populations (Berryhill et al, 2014) and differential effects on various cognitive domains are not well understood To address these ambiguities, we undertook a quantitative review of studies on tDCS in schizophrenia using the PubMed database and identified 194 articles. We undertook a quantitative review of studies on tDCS in schizophrenia using the PubMed database and identified 194 articles This number was reduced to 6 articles after excluding studies on populations without psychosis, without cognitive outcomes, and including only those with a sham stimulation condition to create a sham-adjusted effect size. Study outcomes and heterogeneity of designs were aggregated and variance-weighted
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
