Clinical differences between bipolar disorder and borderline personality disorder: a case report

The clinical difference between bipolar disorder and borderline personality disorder has always been a diagnostic challenge, especially with type II bipolar disorder and subthreshold symptoms, opening a diagnostic bias with the consequent repercussions of inappropriate treatment. Both pathologies are often misdiagnosed initially. The objective of this article is to emphasise the main clinical differences between the two pathologies. We present the case of a patient with a long history of psychiatric symptoms that started in childhood, with considerable functional impairment, who met the criteria for both disorders, pointing to comorbidity. During follow-up, she responded favourably to psychotropic drugs, pushing the diagnosis towards the bipolar spectrum, due to the notable improvement. However, comorbidity should not be neglected due to its high presentation.