BDNF and mood disorder: Brain-derived neurotrophic factor (BDNF) and its receptor TrkB are known to play a role in the maturation of inhibition during post-natal life (McAllister et al., 1999; Hensch, 2005) and deficits in these factors are linked to multiple late-onset psychiatric disorders, including schizophrenia and mood disorders (Rubenstein and Merzenich, 2003; Hashimoto et al., 2004; Lewis et al., 2005).