The neurobiology of borderline personality disorder: the synergy of "nature and nurture".

The author reviews the current state of our knowledge concerning the neurobiology of borderline personality disorder (BPD). A converging body of scientific evidence indicates that patients with BPD suffer from impairments in the brain systems that regulate impulsivity, aggression, and affect. This article reviews data on the neurobiology of the symptoms of BPD, including emotional and behavioral dysregulation, identity disturbance, cognitive impairments, and interpersonal difficulties. The author first considers the evolutionary context in which BPD can develop to put the neurobiological findings in perspective, and then discusses the roles of both genetic inheritance and the environment in the development of BPD. The role of neurotransmitter systems in the development of impulsive-aggression and affective instability is reviewed. Possible neurobiological contributors to the identity disturbance seen in BPD are also described. The author then considers environmental contributions to BPD and discusses the synergy of nature and nurture in the development of BPD symptoms. Findings concerning the types of neurobiological impairments that can arise as a result of childhood neglect and abuse and other types of chronic severe stress and trauma are discussed. Finally, the author reviews studies of animal attachment models that suggest that types of maternal care can produce lifelong behavioral and physiological differences in offspring and that this effect is mediated through the regulation of gene expression. The author suggests that the large body of neuroscience research reviewed in this article suggests that, while patients with BPD may be born with innate genetic tendencies for impaired brain systems for regulating impulses and affect, the environment they find themselves born into may be critical in determining whether or not they develop the full blown syndrome of BPD.