A person with borderline personality disorder (BPD) is acting out their intense pain, fear, and shame using primitive defenses they may have learned long ago. This can take many forms including self-destructive behavior, transient psychotic episodes, emotional and verbal abuse of others, splitting (see below), magical thinking (beliefs that thoughts can cause events), omnipotence, projection of unpleasant characteristics in the self onto others and projective identification (trying to elicit in others the feelings s/he is having).

The etiology of BPD is still unknown. Some believe it to be a true personality disorder caused by childhood trauma, however current research is showing that it is may be a highly genetic, physical brain disorder.

Evidence is showing that the hippocampus, a crucial limbic system component, suffers a significant size reduction in people with BPD. This may partly explain the memory problems associated with BPD, since the hippocampus is a critical location for memory.

Some new statistics
BPD affects one in 50 people and one in five of those people are admitted to psychiatric units in the U.S. One in every 10 people with BPD will die by suicide. Most people have not even heard of the borderline personality disorder.

BPD rarely exists without other diagnoses. Attention Deficit Disorder is the most common. Asperger's Syndrome, temporal lobe dysfunction (Described as a "spaceyness" or "medicine head" feeling in those with BPD. In fact BPD's more severe symptoms are likely a form of temporal lobe epilepsy.), Generalized Anxiety Disorder, Obsessive Compulsive Personality Disorder, Obsessive Compulsive Disorder, Attention Deficit Hyperactive Disorder, rejection sensitivity (along with dysthymia), Panic Disorder, and Cyclothymia are some of the many that are made in conjunction with BPD.

DSM-IV criteria

The DSM-IV gives these nine criteria; a diagnosis requires that the subject present with at least five of these.

Traits involving emotions:

1. Shifts in mood lasting only a few hours.

2. Anger that is inappropriate, intense or uncontrollable.

Traits involving behavior:

3. Self-destructive acts, such as self-mutilation or suicidal threats and gestures that happen more than once. The cuts have to be bloody, and the scars bright red; its sometimes the only way to express the indescribable pain and torment in my mind and soul, that I go through every day of my pathetic existence on this planet.

4. Two potentially self-damaging impulsive behaviors. These could include alcohol and other drug abuse, compulsive spending, gambling, eating disorders, shoplifting, reckless driving, compulsive sexual behavior. Sometimes I feel too much, instead of an empty hole, I'm bleeding to death emotionally. Alcohol slows everything back to numb again. Then the numbness scares the hell out of me and I do something just to remind myself that I'm alive again. Rinse, Repeat.

Traits involving identity

5. Marked, persistent identity disturbance shown by uncertainty in at least two areas. These areas can include self-image, sexual orientation, career choice or other long-term goals, friendships, values. People with BPD may not feel like they know who they are, or what they think, or what their opinions are, or what religion they should be. Instead, they may try to be what they think other people want them to be.

6. Chronic feelings of emptiness or boredom. A deep hole in my stomach. An emptiness that I don't know how to fill.

Traits involving relationships

7. Unstable, chaotic, intense relationships characterized by splitting. The self and others are viewed as "all good" or "all bad." People are either the best or the worst, no concept of middle ground. Something which is all good one day can be all bad the next, which is related to another symptom: borderlines have problems with object constancy in people -- they read each action of people in their lives as if there were no prior context; they don't have a sense of continuity and consistency about people and things in their lives. They have a hard time experiencing an absent loved one as a loving presence in their minds. They also have difficulty seeing all of the actions taken by a person over a period of time as part of an integrated whole, and tend instead to analyze individual actions in an attempt to divine their individual meanings. People are defined by how they last interacted with the borderline. In the same sense of constancy borderlines have "emotional amnesia", they are so completely in each mood, they have great difficulty conceptualizing, remembering what it's like to be in another mood.

8. Frantic efforts to avoid real or imagined abandonment.
Alternating clinging and distancing behaviors (I Hate You, Don't Leave Me). Sometimes you want to be close to someone. But when you get close it feels TOO close and you feel like you have to get some space.
Great difficulty trusting people and themselves. Early trust may have been shattered by people who were close to you. Many borderlines were abused at a young age.
Sensitivity to criticism or rejection. Feeling of "needing" someone else to survive. Heavy need for affection and reassurance (Some people with BPD may have an unusually high degree of interpersonal sensitivity, insight and empathy)

9. Transient, stress-related paranoid ideation or severe dissociation.