Purpose of review: Differentiating bipolar II disorder (BP II) from borderline personality disorder (BPD) is a common diagnostic dilemma. The purpose of this review is to focus on recent studies that have considered clinical differences between the conditions including family history, phenomenology, longitudinal course, comorbidity and treatment response, and which might advance their clinical distinction.
Recent findings: Findings suggest key differentiating parameters to include family history, onset pattern, clinical course, phenomenological profile of depressive and elevated mood states, and symptoms of emotional dysregulation. Less specific differentiation is provided by childhood trauma history, deliberate self-harm, comorbidity rates, neurocognitive features, treatment response and impulsivity parameters.
Summary: This review refines candidate variables for differentiating BP II from BPD, and should assist the design of studies seeking to advance their phenomenological and clinical distinction.