Answer: Borderline personality disorder
Explanation:
Since Marty is moody, manipulative, unstable, lacks a clear sense of identity, and often clings to others, this implies that Marty might be diagnosed with the borderline personality disorder.
Borderline personality disorder is a mental disorder characterised whereby the person affected has unstable behavior, moods, and relationships. In this case, Marty will be instable, impulsive, insecure, and have a feeling of worthlessness.
The treatment of borderline personality disorder is usually through talk therapy or medication.
