Which personality disorder is marked by unstable and unpredictable mood and behavior?

The personality disorder that is characterized by unstable and unpredictable mood and behavior is Borderline Personality Disorder (BPD). Individuals with BPD often experience intense emotional responses that can switch rapidly, leading to dramatic shifts in self-image, relationships, and behavior. This instability can manifest as significant mood swings, impulsive actions, and challenges in maintaining stable relationships.

People with BPD may have a fear of abandonment that can lead them to engage in frantic efforts to avoid perceived rejection, contributing further to emotional volatility. They might struggle with feelings of emptiness and have difficulty regulating their emotions, which can result in tumultuous interpersonal experiences.

The identification of BPD as the correct answer is supported by its hallmark symptoms, distinguishing it from other personality disorders mentioned. For instance, Antisocial Personality Disorder typically involves a disregard for others and societal rules, Avoidant Personality Disorder is marked by feelings of inadequacy and sensitivity to negative evaluation, and Narcissistic Personality Disorder is characterized by grandiosity and a need for admiration rather than instability in mood and behavior. Understanding these nuances helps clarify why Borderline Personality Disorder is specifically marked by instability and unpredictability.