Abstract
In psychopathology, one of the most complex challenges is offered by the diagnostic comparison between patients with borderline personality disorder and those with bipolar spectrum disorder, as some of the symptoms characterizing the two disorders overlap. This detail can mislead therapists who are often called upon to diagnose these syndromes, and in some cases, there is a tendency to diagnose both as one is a personality disorder and the other is a mood disorder. This article provides the reader with a complete overview of these two disorders, highlighting some aspects that could redefine their clinical framework. This need could favor a reduction in cases of diagnostic error, also through the proposal of an innovative psychometric tool, Perrotta Border-Bipolar Profile Diagnostic Questionnaire, currently being validated.