Frontal electroencephalogram changes in early phase antidepressant treatment predict clinical response in major depressive disorder

The investigators of the Biomarkers for Rapid Identification of Treatment Effectiveness in Major Depression (BRITE-MD) study calculated the Antidepressant Treatment Response (ATR) index, a biomarker of frontal quantitative electroencephalogram changes, af ter 1 week of escitalopram treatment and examined whether the ATR had utility as a predictor of outcome after a further 7 weeks of treatment. The ATR index predicted response and remission at week 7, whereas the symptom reduction in Hamilton Depression Rating Scale scores by week 1 only predicted response at week 7. Other markers, such as genetic polymorphisms (5-HTTLPR and 5HT2A), the clinician-rated global impression of improvement and serum drug concentrations, did not provide significant predictive utility. Notably, high ATR values predicted response to escitalopram, while low ATR values predicted response to bupropion. The findings provocatively suggest that the ATR index may be a useful predictor for short-term antidepressant outcome. These results may encourage the future work that will be necessary to evaluate the role of the ATR index and clinical measures as predictors of both short-and long-term antidepressant treatment outcomes.