FGF2 and major depressive disorder: Changes in Fgfr1 expression, and FGF2 levels in the hippocampus are linked to major depression and anxiety, as well as to responses to antidepressants (Evans et al., 2004; Newton & Duman, 2004; Gaughran et al., 2006; Turner et al., 2008; Elsayed et al., 2012).