In the course of borderline personality disorder, patients struggle with quite intractable difficulties - it is difficult for them to function even with their closest people. It is for this reason that researchers continue to search not only for the causes by which this problem occurs, but also for factors that may lead to the worsening of borderline patients. A study conducted by researchers at the University of Illinois at Chicago shows that the severity of the manifestations of this disorder in women may be related to menstruation and the period immediately preceding it.