Impulsive aggressive behavior disorders such as intermittent explosive disorder (IED) are often seen as simply ‘bad behavior’ that has to be treated by a psychiatrist. New research recently published in the journal Neuropsychopharmacology, now suggests that this behavior has a biological basis that can be studied and treated.
Royce Lee, MD, is an associate professor of behavioral neuroscience and psychiatry at the University of Chicago. He believes the problem does not lie in how the brain is structured, but relates to how different regions of the brain are connected to each other. A region of the brain called the superior longitudinal fasciculus (SLF) connects the brain’s frontal lobe with the parietal lobe. In people with IED, the white matter in the SLF has less density and integrity than in people with other psychiatric disorders and healthy individuals. The white matter is the brain’s natural wiring between the lobes.
The parietal lobe of the brain processes language and sensory input, while the frontal lobe is responsible for decision-making, understanding consequences of actions and emotion. Less density and integrity in the SLF (also referred to as the ‘information superhighway’ of the brain) can lead to impaired social cognition.
People with anger issues don’t take in all the data from a social interaction, often missing certain words or body language. They interpret others are being hostile when this is not the case, and notice only things that reinforce their belief that they are being challenged. This leads to them making the wrong conclusions about other people in social situations, which results in the misunderstanding of other’s intentions, causing them to react inappropriately to the situation.
If the areas of the brain that process a social situation experiences decreased connectivity, it could lead to reduced judgment that ultimately leads to an explosive outburst of anger. The discovery of connectivity shortfalls in a specific region of the brain such as the SLF, offers an important starting point for more research on not only people with IED, but also those with borderline personality disorder.
People with borderline personality disorder share similar social and emotional problems as those with IED. The study now suggests that both groups also seem to have the same abnormality in the SLF. The brains of healthy individuals exhibit very few (if any) physical differences from people with psychiatric disorders. That makes connectivity between the lobes a critical issue that Lee and his colleagues, Ellen C. Manning Professor and Chair of Psychiatry and Behavioral Neuroscience at the University Chicago and senior author Emil Coccaro, MD, focused on. They used a form of magnetic resonance imaging (MRI) called diffusion tensor imaging, to measures the density and volume of white matter connective tissue in the brain.
Lee, the lead author of the study, concludes that the results point to social cognition being an important area to think about when dealing with people that have anger problems.