BDNF has been implicated in both normative neurocognitive functioning, as well as the pathophysiology in certain psychiatric conditions (e.g., bipolar disorder, post-traumatic stress disorder) [148–151]; however, recent research has suggested that polymorphisms in the BDNF gene may have a large influence on determining the role of BDNF in such conditions [152,153]. Here, BDNF is linked to bipolar disorder.