Antidepressant effects of tDCS are associated with prefrontal gray matter volumes at baseline: Evidence from the ELECT-TDCS trial

• Published in: Brain stimulation Vol. 12; no. 5; pp. 1197 - 1204
• Main Authors: Bulubas, Lucia, Padberg, Frank, Bueno, Priscila V., Duran, Fabio, Busatto, Geraldo, Amaro, Edson, Benseñor, Isabela M., Lotufo, Paulo A., Goerigk, Stephan, Gattaz, Wagner, Keeser, Daniel, Brunoni, Andre R.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.09.2019
• Subjects: Adult; Antidepressant response; Antidepressive Agents, Second-Generation - therapeutic use; Citalopram - therapeutic use; Depressive Disorder, Major - diagnostic imaging; Depressive Disorder, Major - therapy; Double-Blind Method; Female; Gray Matter - diagnostic imaging; Humans; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Major depressive disorder; Male; Middle Aged; Noninvasive brain stimulation; Organ Size; Prefrontal Cortex - diagnostic imaging; Structural neuroanatomy; Transcranial direct current stimulation; Transcranial Direct Current Stimulation - methods; Treatment Outcome; ACC; HDRS-17; pACC; RCT; Noninvasive brain stimulation; Structural neuroanatomy; DLPFC; OLE; sgACC; MDD; PFC; Transcranial direct current stimulation; ROI; Major depressive disorder; NTBS; Magnetic resonance imaging; Antidepressant response; tDCS; ECT; ELECT-TDCS; rTMS; BA
• ISSN: 1935-861X; 1876-4754
• DOI: 10.1016/j.brs.2019.05.006

Transcranial direct current stimulation (tDCS) is a promising intervention for major depression. However, its clinical effects are heterogeneous. We investigated, in a subsample of the randomized, clinical trial Escitalopram versus Electrical Direct Current Therapy for Depression Study (ELECT-TDCS), whether the volumes of left and right prefrontal cortex (PFC) and anterior cingulate cortex (ACC) were associated with prefrontal tDCS response. Baseline structural T1 weighted MRI data were analyzed from 52 patients (15 males). Patients were randomized to the following conditions: escitalopram 20 mg/day, bifrontal tDCS (2 mA, 30min, 22 sessions), or placebo. Antidepressant outcomes were assessed over a treatment period of 10 weeks. Voxel-based gray matter volumes of PFC and ACC were determined using state-of-the-art parcellation approaches. According to our a priori hypothesis, in the left dorsal PFC, larger gray matter volumes were associated with depression improvement in the tDCS group (n = 15) compared to sham (n = 21) (Cohen's d = 0.3, 95% confidence interval [0.01; 0.6], p = 0.04). Neither right PFC nor ACC volumes were associated with depression improvement. Exploratory analyses of distinct PFC subregions were performed, but no area was associated with tDCS response after correction for multiple comparisons. Left PFC baseline gray matter volume was associated with tDCS antidepressant effects. This brain region and its subdivisions should be investigated further as a potential neurobiological predictor for prefrontal tDCS treatment in depression and might be correlated with tDCS antidepressant mechanisms of action. •Three arm, parallel design comparing tDCS, escitalopram, and placebo (ELECT-TDCS).•Association of antidepressant effects and prefrontal cortex volume found for tDCS.•This association was seen in detail for medial prefrontal regions.•No association of antidepressant effects with anterior cingulate cortex volumes.