Treatment resistant depression (TRD) is typically defined as having failed two antidepressant
trials of adequate dosage and duration.1 In older adults, TRD is associated with poor
long-term outcomes including disability, cognitive dysfunction,2 and excess mortality
from suicide.3–7 For older adults with TRD, treatment options supported by evidence
from randomized-controlled trials (RCTs) are limited to aripiprazole augmentation,
with weaker evidence supporting the use of lithium augmentation, combination of antidepressants,
repetitive transcranial magnetic stimulation (rTMS), and electroconvulsive therapy
(ECT).