The Biological Basis of Borderline Personality Disorder (BPD)
According to the biosocial model of borderline personality disorder, BPD is the result of a complex interaction between biological vulnerabilities and the environment, which results in the development of the disorder. Of special interest are invalidating environments- those in which children’s emotional experiences are ignored, belittled, otherwise invalidated by caretakers. In some cases, this emotional mistreatment occurs along with verbal, physical or sexual abuse.
The biological vulnerabilities of interest are related to hyperreactivity (sensitive to cues, especially to negative stimuli) and hyperarousal (a higher baseline level of emotion, with a slower return to baseline). Research on borderline personality disorder in the biological sciences attempts to identify the genetic source of these vulnerabilities.
One current focus of research are genes governing the stress response, located in the the hypothalamic-pituitary-adrenal (HPA) axis. These region of the brain determines how people respond to stress, from interpersonal conflict to encountering a wild animal.
Future research will continue to identity relevant genes, while also examining epigenetic effects- the switching on or off of genes in response to the environment. That is, events such as child abuse can “activate” certain genes implicated in BPD. Eventually, it may be possible to “deactivate” those genes through medical intervention (gene therapy). It is also possible implicated genes do “turn off” over time in response to corrective environmental experiences (which can include therapy, such as DBT).