BackgroundAlthough the diagnosis of Borderline Personality Disorder (BPD) during adolescence has been questioned, many recent studies have confirmed its validity. However, some clinical manifestations of BPD could be identifiable in adolescents with other pathologies, such as Attention-Deficit/Hyperactivity Disorder (ADHD). The objective of the present study is to examine the capacity of the self-report Borderline Personality Features Scale Children-11 (BPFSC-11) to discriminate between BPD and ADHD adolescents.MethodsOne hundred and forty-five participants were grouped based on their diagnosis: 58 with BPD, 58 with ADHD, and 29 healthy volunteers as a control group. Between-group differences and the ROC curve were performed to test if the total score for the BPFSC-11 and/or its factors can significantly discriminate between BPD and other adolescent groups.ResultsThe results show that the total BPFSC-11 score has good discriminant capacity among adolescents diagnosed with BPD, ADHD and healthy volunteers. However, different patterns of discriminative capacity were observed between the three groups for emotional dysregulation and impulsivity/recklessness factors.ConclusionsOur results support the hypothesis that the BPFSC-11 is an adequate instrument for discriminating between BPD and ADHD in adolescents, who can present significant psychopathological overlap. Tools to identify BPD in adolescence, as well as for better differential diagnosis, would improve the possibility of offering specific treatments targeting these populations.