Results of the studies in MDD are more conflicting, with fewer publications concerning first-episode patients [58,59,60,61], showing elevated [58,59,60,61,63,64,65], decreased [61,62,72,73], or no differences [60,61,66,67,68,69,70,71] in S100B levels compared to HC. This evidence concerns the gene S100B and major depressive disorder.