Borderline Personality Disorder:

A person who suffers from this disorder has labile interpersonal relationships characterized by instability. This pattern of interacting with others has persisted for years and is usually closely related to the person's self-image and early social interactions. The pattern is present in a variety of settings (e.g., not just at work or home) and often is accompanied by a similar lability (fluctuating back and forth, sometimes in a quick manner) in a person's affect, or feelings. Relationships and the person's affect may often be characterized as being shallow. A person with this disorder may also exhibit impulsive behaviors and exhibit a majority of the following symptoms:

frantic efforts to avoid real or imagined abandonment.

a pattern of unstable and intense interpersonal relationships characterized by alternating between extremes of idealization and devaluation.

identity disturbance: markedly and persistently unstable self-image or sense of self

impulsivity in at least two areas that are potentially self-damaging (e.g., spending, sex, substance abuse, reckless driving, binge eating)

recurrent suicidal behavior, gestures, or threats, or self-mutilating behavior

affective instability due to a marked reactivity of mood (e.g., intense episodic dysphoria, irritability, or anxiety usually lasting a few hours and only rarely more than a few days)

chronic feelings of emptiness

inappropriate, intense anger or difficulty controlling anger (e.g., frequent displays of temper, constant anger, recurrent physical fights)
transient, stress-related paranoid ideation or severe dissociative symptoms