Examining relations between alpha power as well as anterior cingulate cortex-localized theta activity and response to single or dual antidepressant pharmacotherapies

Abstract

Electrocortical indices may be useful in predicting antidepressant response. Greater pretreatment alpha power and high rostral anterior cingulate cortex (rACC) theta activity tend to index a favorable outcome. The predictive utility of alpha power asymmetry has been under-explored. Baseline alpha2 (10.5-13.0 Hz) power/asymmetry, rACC theta2 (6.0-8.0 Hz) activity and early (one week) changes in these measures were assessed in relation to antidepressant response by week 12 to three treatment regimens (escitalopram (ESC) + bupropion (BUP), ESC or BUP) in patients with major depressive disorder (N=51). No treatment differences in response existed at week 12. Overall, treatment responders exhibited high, and non-responders low, frontal baseline alpha2 power. Frontal alpha2 power weakly discriminated responders/non-responders overall while posterior alpha2 power and BA25-localized theta2 activity strongly discriminated ESC responders/non-responders. No associations with alpha2 asymmetry and response emerged. BUP responders exhibited high, and BUP non-responders low, baseline rACC theta2 activity. Greater early decreases in rACC theta2 activity existed in ESC+BUP non-responders versus ESC+BUP responders. BUP responders exhibited greater rACC theta2 activity decreases than ESC responders. These preliminary results indicate that baseline and early changes in alpha2 and rACC theta2 activity associate with response and have implications for tailoring antidepressant treatments.