The present trial consists of 2 sub-studies that investigate important novel aspects of treatment with erythropoietin (EPO) on cognitive dysfunction in bipolar disorder (BD). The aims of the trial are three-fold. We aim to investigate the effects of 12 weekly recombinant human EPO infusions on cognition in (i) healthy first-degree relatives of BD patients (substudy 1) and (ii) remitted BD patients (substudy 2), and (iii) explore early treatment-associated neural activity changes that may predict subsequent cognitive improvement.