Which personality disorder includes a pattern of unstable and intense interpersonal relationships?

The personality disorder characterized by unstable and intense interpersonal relationships is Borderline Personality Disorder (BPD). Individuals with BPD often experience significant fluctuations in their relationships, swinging between idealization and devaluation of others. This can lead to tumultuous relationships, where they may feel extremely close to someone one moment and then feel angry or disconnected the next. This instability is often rooted in a deep fear of abandonment and can lead to impulsive behaviors in how they relate to others.

While other personality disorders may exhibit certain interpersonal difficulties, they do not specifically embody the pattern of instability seen in BPD. For instance, individuals with Schizoid Personality Disorder tend to avoid close relationships altogether, choosing to remain solitary. Antisocial Personality Disorder is characterized more by disregard for others' rights and lack of empathy, focusing on manipulative relationships rather than instability. Histrionic Personality Disorder involves a need for attention and may feature theatrical behavior, but it does not capture the same degree of relationship turmoil that is hallmark to Borderline Personality Disorder. The defining features of BPD make it the clear answer when identifying the disorder related to unstable and intense interpersonal relationships.