Self‐report screening instruments differentiate bipolar disorder and borderline personality disorder

Background Bipolar disorder (BD) and borderline personality disorder (BPD) share overlapping phenomenology and are frequently misdiagnosed. This study investigated the diagnostic accuracy of the Mood Disorder Questionnaire (MDQ) and McLean Screening Instrument for Borderline Personality Disorder (MSI) in a clinical inpatient setting and whether individual screening items could differentiate BD from BPD. Methods 757 sequential inpatients admitted to a Mood Disorder Unit completed both the MDQ and MSI. Screen positive for the MDQ was defined as ≥7/13 symptoms endorsed with concurrence and at least moderate impact. Screen positive for the MSI was defined as a score of ≥7. The clinical discharge summary diagnosis completed by a board‐certified psychiatrist was used as the reference standard to identify concordance rates of a positive screen with clinical diagnosis. Individual items predicting one disorder and simultaneously predicting absence of other disorder by odds ratio (OR>and
1. Clinical differentiation between bipolar disorder and borderline personality disorder can be challenging as both disorders share certain features like impulsivity, mood lability, and affective instability.2. The results from this study offer practical and useful clinical guidance for focusing on specific sub‐items from the Mood Disorder Questionnaire (MDQ) and McLean Screening Instrument for borderline personality disorder (MSI) that can help distinguish bipolar disorder and borderline personality disorder.