Which symptom is a hallmark of borderline personality disorder?

The hallmark symptom of borderline personality disorder (BPD) is characterized by intense and unstable relationships. Individuals with BPD often experience fluctuating feelings towards others, swinging between idealization and devaluation. This pattern leads to tumultuous interpersonal relationships where they may feel deeply connected one moment and then become angry or distant the next. This instability stems from an intense fear of abandonment and can result in significant difficulties in maintaining healthy, stable relationships.

The other symptoms listed, while they can be present in individuals with BPD, do not capture the essence of the disorder as effectively as the hallmark of relationship instability. Chronic low mood may be associated with various mental health conditions, including mood disorders. Compulsive behaviors are often linked to disorders like obsessive-compulsive disorder rather than BPD specifically. Withdrawal from social interactions is more characteristic of conditions like social anxiety or depression rather than the relational tumult seen in borderline personality disorder.