BDNF and Borderline personality disorder: BDNF methylation was significantly higher in both exon 1 and exon 4 CpG regions in BPD than in control subjects. The number of CT was significantly positive correlated with methylation levels. In BPD, BDNF methylation was significantly increased after I-DBT in both CpG-regions. This increase was decisively caused by the I-DBT nonresponders. I-DBT responders showed a decrease of methylation. No significant association of BDNF methylation with protein plasma levels.