“…For example, group-level predictive correlations to outcome have been reported for serotonin transporter and brain-derived neurotrophic factor genetic polymorphisms [15,16], biochemical measures such as cortisol [17,18], baseline regional cerebral perfusion or metabolism on PET and SPECT [19e24], resting-state functional MRI [8,25,26], quantitative EEG metrics [27], and electrophysiological measures such as motor evoked potential amplitude, cortical silent period, or short-interval cortical inhibition [28]. A smaller number of studies have actually reported individual-level outcome prediction accuracies >80% for specific biomarkers, including quantitative EEG [29,30], and most recently, resting-state functional MRI [31]. Such developments are promising, but measures such as fMRI and TMS-electrophysiology are not readily available outside academic centers, limiting clinical utility.…”