People who experience sudden aggressive rage attacks have smaller “emotional brains,” according to new research findings out of the University of Chicago.

The findings, reported in the journal Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, indicate individuals with a condition known as “intermittent explosive disorder” (IED) have significantly lower gray matter volume in the “frontolimbic” regions of the brain that govern emotions.

In other words, these people have smaller "emotional brains" and that biological reality may play an important role in aggressive behavior.

"Intermittent explosive disorder is defined in DSM-5 as recurrent, problematic, impulsive aggression," explained lead researcher Dr. Emil Coccaro, a professor of psychiatry and behavioral neuroscience.

"While more common than bipolar disorder and schizophrenia combined, many in the scientific and lay communities believe that impulsive aggression is simply 'bad behavior' that requires an 'attitude adjustment.' However, our data confirm that IED, as defined by DSM-5, is a brain disorder and not simply a disorder of 'personality.' "

To reach their conclusions, investigators collected high-resolution magnetic resonance imaging (MRI) scans of 168 subjects, including 57 subjects with IED, 53 healthy people, and 58 with psychiatric disorders.

The team found a direct correlation between a history of aggressive behavior and the magnitude of reduction in gray matter volume.