Borderline personality disorder is characterized by severe functional impairment, a high risk of suicide, a negative impact on the course of depressive disorders, extensive treatment, and high costs to society. The course of this disorder is less stable than expected for other personality disorders. The specific causes are not yet fully understood, but genetic factors and adverse life events and circumstances, especially in early childhood, seem to interact to produce the disorder. Neurobiological research indicates that abnormalities in the frontal limbic networks are associated with many symptoms. Data on the effectiveness of targeted psychopharmacotherapy in the treatment of BPD vary and the evidence is not yet firm, but it is known to be of considerable help in the treatment of severe forms of the disease, specific symptoms as well as certain comorbidities. Certain forms of psychotherapy have proved to be extremely helpful in dealing with the problems that often occur in borderline personality disorder patients. Further research on diagnosis, neurobiology and treatment is needed to identify a specific cause, establish ideal guidelines and criteria for diagnosis, and identify the most appropriate therapeutic approach.