BDNF and major depressive disorder: Taken together, results from our study and the recent study by Woudstra and colleagues [39] indicate that verbal emotional memory bias may not be strongly associated with the PCLO rs2522833 polymorphism - unlike other genes that have been associated with both memory bias and depression (e.g. BDNF, NR3C2) - and may be implicated in other routes towards the susceptibility for depression.