Monday, March 9, 2009
BPD and the Brain
Borderline Personality Disorder and the Brain
Borderline Personality Disorder (BPD) is an emotional disorder. People with this disorder tend to react to situations differently; they experience intense emotions that can at times change rapidly, yet at other times they linger for a torturously long time. People with BPD may have trouble calming themselves down after feeling a strong emotion. (Linehan, 2007)
As we know from our readings, the brain can change for any number of reasons, such as genes; exposure to unhealthy conditions or substances during gestation; stressful events during infancy, childhood, or later trauma; alcohol and/or substance abuse.
The areas of the brain that may be involved in BPD include the limbic system, the prefrontal cortex, and the hypothalamic-pituitary-adrenal axis.
Limbic System and Prefrontal Cortex
As we have learned in class, the limbic system is an area of the brain that among other things, has to do with emotions, memory, and pleasure. The amygdala, the emotional center of the brain, and the hippocampus, which is involved in learning and memory, are included in the limbic system.
Studies have shown that people with BPD have smaller amygdalas, and certain areas of the amygdala are more reactive to emotional stimulation. (Schmal et al. 2003; Tebartz van Elst et al. 2003) In one study, the amygdala was monitored to see how it reacted to faces with different types of emotional expressions. People with BPD had stronger activation in their left amygdalas. (Herperts et al. 2001)
Research has shown that people with BPD also tend to have a smaller hippocampus.than those who do not. (Schmal et al. 2003; Tebartz van Elst et al. 2003) Similarly, people with post-traumatic stress disorder (PTSD) tend to have a smaller hippocampus, but people with BPD are the only ones who have smaller hippocampi and amygdalas.
The prefrontal cortex, the piece of the brain whose importance was made most famous by Phineas Gage, shows evidence that it is involved in the activity of the limbic system. In fact, this evidence seems to suggest that activity in the prefrontal cortex regulates activity in this emotional center of the brain. Research on BPD demonstrates lower activity in patients in certain areas of the prefrontal cortex when they are exposed to stressful memories. (Schmal et al. 2003) This suggests that low activity in the prefrontal cortex may not be active enough in certain ways to effectively regulate the amydala, causing the person’s intense emotions to make them feel as if they are “spinning out of control.”
The Hypothalamic-Pituitary-Adrenal Axis
The HPA axis is the other neurological system related to the brain. Both the hypothalamus and pituitary gland influence the body’s response to stress, and higher activity in the HPA axis leads to greater concentrations of cortisol, the stress hormone. A hyperactive HPA axis means a hyperactive biological stress response.
People who have BPD can get thrown over the edge over even minor stressors, and may go through periods of extremely tense irritability. In other words, they have an exaggerated stress response.
People with BPD demonstrate exaggerated cortisol responses compared to people without BPD. (Grossman, Yehuda, and Siever 1997; Lieb Rexhausen, et al. 2004.) Other research has shown that a hyperactive HPA axis may predispose people to attempt suicide. (van Heeringen et al. 2000)
Stressful and/or traumatic events can also increase the likelihood of exaggerated cortisol levels.
There are also several theories about dopamine and serotonin genes which I will talk about tomorrow in my presentation!