We reviewed the available evidence of the effects of psychotherapy on changes in DNA methylation and conducted a pilot study in a sample of 11 female adolescents diagnosed with BPD, exploring for changes in peripheral DNA methylation of FKBP5 gene, which encodes for a stress response protein, in relation to psychotherapy, on symptomatology and underlying psychological processes. This evidence concerns the gene FKBP5 and Borderline personality disorder.