[Boundaries, borders, limits].
Although social and cultural changes in the last decades have produced subjective imbalances, according to the author, they only provoke ruptures or disorganize when they find a psyche that has previous leaks or serious flaws in its constitution. This is the case in the borderline disorder. This hypothesis is developed throughout the article and it is articulated with a clinical case of a borderline patient, as an example. From the study of the analyst patient relationship, a dynamic statement of the signs and symptoms and the changes in technique and framework is made. This pathology is included among narcissistic diseases. According to some analysts, it explains most of the clinical demand nowadays. They are called "present pathologies", which doesn't mean they haven't existed for a long time. It means that, at present, besides paying attention to the paths of desire, psychoanalysts listen to the narcissistic vicissitudes of existence, identity and self esteem; not only in patients with ego pathologies but also in the narcissistic disturbances of neurotics. This is the reason why making a diagnosis is sometimes so difficult.