BDNF and mood disorder: Furthermore, there are reciprocal associations between BDNF and immune-inflammatory pathways, which may explain the involvement of BDNF in the immune pathophysiology of mood disorders (Perrot and Russell, 2014), with BDNF acting as a conserved regulatory process that protects against the detrimental effects of immune activation including neurotoxicity (Mehterov et al., 2022).