Finally, in order to test whether the effect remained after discontinuation of the trial medication, adding the follow-up visit in week 14, six weeks after treatment completion, there was still a trend towards reduction in BDNF levels in the EPO-treated TRD patients (F = 2.33, p = 0.098, partial ŋ2 = 0.06). Here, BDNF is linked to treatment resistant depression.