The comparative effectiveness of electroencephalographic indices in predicting response to escitalopram therapy in depression: A pilot study

J Affect Disord. 2018 Feb;227:542-549. doi: 10.1016/j.jad.2017.10.028. Epub 2017 Nov 3.


Background: This study aims to compare the effectiveness of EEG frequency band activity including interhemispheric asymmetry and prefrontal theta cordance in predicting response to escitalopram therapy at 8-weeks post-treatment, in a multi-site initiative.

Methods: Resting state 64-channel EEG data were recorded from 44 patients with a diagnosis of major depressive disorder (MDD) as part of a larger, multisite discovery study of biomarkers in antidepressant treatment response, conducted by the Canadian Biomarker Integration Network in Depression (CAN-BIND). Clinical response was measured at 8-weeks post-treatment as change from baseline Montgomery-Asberg Depression Rating Scale (MADRS) score of 50% or more. EEG measures were analyzed at (1) pre-treatment baseline (2) 2 weeks post-treatment and (3) as an ''early change" variable defined as change in EEG from baseline to 2 weeks post-treatment.

Results: At baseline, treatment responders showed elevated absolute alpha power in the left hemisphere while non-responders showed the opposite. Responders further exhibited a cortical asymmetry in the parietal region. Groups also differed in pre-treatment relative delta power with responders showing greater power in the right hemisphere over the left while non-responders showed the opposite. At 2 weeks post-treatment, responders exhibited greater absolute beta power in the left hemisphere relative to the right and the opposite was noted for non-responders. A reverse pattern was noted for absolute and relative delta power at 2 weeks post-treatment. Responders exhibited early reductions in relative alpha power and early increments in relative theta power. Non-responders showed a significant early increase in prefrontal theta cordance.

Conclusions: Hemispheric asymmetries in the alpha and delta bands at baseline and at 2 weeks post-treatment have moderately strong predictive utility in predicting response to antidepressant treatment.

Keywords: Alpha asymmetry; Depression; EEG power; Escitalopram; Theta cordance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antidepressive Agents, Second-Generation / therapeutic use*
  • Canada
  • Cerebral Cortex / drug effects
  • Citalopram / therapeutic use*
  • Comparative Effectiveness Research
  • Depressive Disorder, Major / drug therapy*
  • Depressive Disorder, Major / psychology
  • Electroencephalography*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Pilot Projects
  • Treatment Outcome


  • Antidepressive Agents, Second-Generation
  • Citalopram