Cognitive outcomes after tDCS in schizophrenia patients with prominent negative symptoms: Results from the placebo-controlled STARTS trial

Cognitive deficits and negative symptoms in schizophrenia are associated with poor functional outcomes and limited in terms of treatment. The Schizophrenia Treatment With Electric Transcranial Stimulation (STARTS) trial has shown efficacy of transcranial direct current stimulation (tDCS) for improving negative symptoms. In this secondary analysis, we investigate its effects on cognitive performance. In STARTS, a double-blinded, sham controlled, randomized clinical trial, patients were treated with twice-daily, 20-min, 2-mA fronto-temporal tDCS over 5 days or sham-tDCS. In 90 patients, we evaluated the cognitive performance up to 12 weeks post-treatment. We found that active-tDCS showed no beneficial effects over sham-tDCS in any of the tests. Based on a 5-factor cognitive model, improvements of executive functions and delayed memory were observed in favor of shamtDCS. Overall, the applied active-tDCS protocol, primarily designed to improve negative symptoms, did not promote cognitive improvement. We discuss possible protocol modification potentially required to increase tDCS effects on cognition. ClinicalTrials.gov identifier: NCT02535676

Automated summary

The study found that transcranial direct current stimulation (tDCS) did not effectively improve cognitive function in patients with schizophrenia, and sham-tDCS performed better in some tests. This suggests that modifications to the tDCS treatment protocol may be needed to enhance its effects on cognition.