Diagnostic criteria for borderline personality disorder (BPD) and mood and psychotic disorders characterized by major mood episodes (i.e., major depressive, bipolar and schizoaffective disorder) share marked overlap in symptom presentation, complicating differential diagnosis. The current study tests the hypothesis that maladaptive interpersonal schemas (MIS) are characteristic of BPD, but not of the major mood disorders. One hundred psychiatric inpatients were assessed by SCID I, SCID II and the Young Schema Questionnaire (YSQ-S2). Logistic regression analyses tested the association between MIS (measured by the YSQ-S2) and BPD, bipolar, major depressive and schizoaffective disorder. Receiver operator characteristic (ROC) curve analyses assessed the sensitivity and specificity of MIS as a marker of BPD. After covariation for comorbidity with each of the 3 mood disorders, BPD was robustly associated with 4 out of 5 schema domains. In contrast, only one of fifteen regression analyses demonstrated a significant association between any mood disorder and schema domain after covariation for comorbid BPD. ROC analyses of the 5 schema domains suggested Disconnection/Rejection had the greatest power for identification of BPD cases. These data support the specific role of maladaptive interpersonal schemas in BPD and potentially contribute to greater conceptual clarity about the distinction between BPD and the major mood disorders. (C) 2016 Elsevier Ireland Ltd. All rights reserved.