Final answer:
Borderline personality disorder is characterized by instability in mood, interpersonal relationships, and a pronounced difficulty with being alone. These symptoms can also be influenced by temperament and childhood environments.
Step-by-step explanation:
Instability in mood, instability within relationships, and difficulty being alone are all characteristics of borderline personality disorder. While other disorders such as avoidant, schizoid, and antisocial personality disorders also impact interpersonal relationships and emotional stability, borderline personality disorder is distinct in its pattern of intense and unstable relationships, as well as significant mood swings and fear of abandonment. Individuals with this disorder may experience intense episodes of anger, depression, and anxiety that can last from a few hours to days. Temperament, childhood environment, and psychopathology are considered crucial factors that can contribute to the development of personality disorders like borderline personality disorder.