From the National Institutes of Mental Health (NIMH)

Although the cause of BPD is unknown, both environmental and genetic factors are thought to play a role in predisposing patients to BPD symptoms and traits. Studies show that many, but not all individuals with BPD report a history of abuse, neglect, or separation as young children. A significant percentage of BPD patients report having been sexually abused, usually by people outside of the close family. Researchers believe that BPD results from a combination of individual vulnerability to environmental stress, neglect or abuse as young children, and a series of events that trigger the onset of the disorder as young adults. Adults with BPD are also considerably more likely to be the victim of violence, including rape and other crimes. This may result from both harmful environments as well as impulsivity and poor judgment in choosing partners and lifestyles.

NIMH-funded neuroscience research is revealing brain mechanisms underlying the impulsively, mood instability, aggression, anger, and negative emotion seen in BPD. Studies suggest that people predisposed to impulsive aggression have impaired regulation of the neural circuits that modulate emotion. The amygdala, a small almond-shaped structure deep inside the brain, is an important component of the circuit that regulates negative emotion. In response to signals from other brain centers indicating a perceived threat, it marshals fear and arousal. This might be more pronounced under the influence of drugs like alcohol, or stress. Areas in the front of the brain (pre-frontal area) act to dampen the activity of this circuit. Recent brain imaging studies show that individual differences in the ability to activate regions of the prefrontal cerebral cortex thought to be involved in inhibitory activity predict the ability to suppress negative emotion.

Serotonin, nor epinephrine and acetylcholine are among the chemical messengers in these circuits that play a role in the regulation of emotions, including sadness, anger, anxiety and irritability. Drugs that enhance brain serotonin function may improve emotional symptoms in BPD. Likewise, mood-stabilizing drugs that are known to enhance the activity of GABA, the brain's major inhibitory neurotransmitter, may help people who experience BPD-like mood swings. Such brain-based vulnerabilities can be managed with help from behavioral interventions and medications, much like people manage susceptibility to diabetes or high blood pressure.

Future Progress

Studies that translate basic findings about the neural basis of temperament, mood regulation and cognition into clinically relevant insights—which bear directly on BPD—represent a growing area of NIMH-supported research. Research on DBT, TFP, psychodynamic psychotherapy, other cognitive therapies, supportive psychotherapy and medications is also underway to test these treatments and combinations of therapy. Data from the first prospective, longitudinal study of BPD, which began in the early 1990s, is expected to reveal how treatment affects the course of the illness. It will also pinpoint specific environmental factors and personality traits that predict a more favorable outcome. The Institute is also collaborating with a private foundation to help attract new researchers to develop a better understanding and better treatment for BPD.