Cognitive outcomes of the bipolar depression electrical treatment trial (BETTER): a randomized, double-blind, sham-controlled study

Bipolar depression is associated with marked cognitive deficits. Pharmacological treatments for this condition are limited and may aggravate depressive and cognitive symptoms. Therefore, therapeutic interventions that preserve adequate cognitive functioning are necessary. Our previous results demonstrated significant clinical efficacy of transcranial direct current stimulation (tDCS) in the Bipolar Depression Electrical Treatment Trial (BETTER). Here, cognitive outcomes of this study are reported. We randomized 59 patients with bipolar disorder I or II in an acute depressive episode to receive active (12 2 mA, 30-min, anodal-left, cathodal-right prefrontal cortex tDCS sessions) or sham tDCS. Patients were on stable pharmacological regimen for at least 2 weeks. A battery of 12 neuropsychological assessments in five cognitive domains (attention and processing speed, memory, language, inhibitory control, and working memory and executive function) was performed at baseline, after two weeks and at endpoint (week 6). No significant differences between groups over 6 weeks of treatment were observed for any cognitive outcomes. Moreover, no decrease in cognitive performance was observed. Our findings warrant further replication in larger studies. Trial Registration: clinicaltrials.gov Identifier: NCT02152878

Automated summary

The study found that cognitive performance of patients with bipolar depression did not significantly change during transcranial direct current stimulation (tDCS) treatment, and there was no decrease in cognitive function. These results need to be further replicated in larger studies.