Borderline Personality Disorder
The Encyclopedia of Mental Disorders defines Borderline Personality Disorder as a mental disorder “characterized by disturbed and unstable interpersonal relationships and self image, along with impulsive, reckless, and often self-destructive behavior.” 
Adults with Borderline Personality Disorder have a difficult time viewing people significant in their lives; those people seem either extremely unfair or uncaring or absolutely flawless. Individuals with BPD either devalue or idealize those important to them – this behavior is called “splitting,” according to the Encyclopedia of Mental Disorders.
Some causes of BPD include childhood traumas such as physical or sexual abuse, loss of a parental figure, or parental neglect. The child begins to develop feelings of self-dislike and inadequacy as a result of his or her life situations; this may be one cause of the development of BPD. As the person with BPD grows into adulthood, he tries to compensate for the mistreatment or neglect by establishing highly idealized demands on himself and others.
The symptoms of BPD include efforts to avoid either real or perceived abandonment; a pattern of intense and unstable interpersonal relationships that are characterized by alternating between idealization and devaluation; impulsive behaviors in at least two areas (binge eating, sexual acting-out, substance abuse, or reckless driving); persistent and unstable self-image and sense of self; recurrent suicidal behaviors, including threats and gestures or acts of self-mutilation (cutting or burning); unstable moods – irritability, depression, or anxiety; always feeling “empty;” intense and inappropriate anger, difficulty controlling anger outbursts, which is characterized by sarcasm and/or physical fighting; paranoia caused by stress, which passes quickly; dissociative symptoms, or feeling disconnected from the physical self, as if observing actions from outside.
The Encyclopedia of Mental Disorders points out that, in diagnosis, BPD “commonly” occurs with mood disorders, PTSD, eating disorders, ADHD, and other personality disorders.