Angry outbursts linked to brain dysfunction. In my work as a psychiatrist, I have paid much attention to the relatively neglected, related areas of irritability, anger dyscontrol, impulsivity and violence. In the extreme, patients with a degree of impulsive angry outbursts warranting a psychiatric diagnosis are labelled with intermittent explosive disorder. Not surprisingly, IED is associated with dysfunction of frontal lobe areas; the frontal cortex, among other things, mediates inhibition and control of impulsive behaviors.

What is interesting about this study is that patients with IED differ from controls in some other aspects of frontal lobe function, and particularly those mediated by a particular frontal subregion called the orbitomedial prefrontal cortex (OMPF) — observed to be impaired in patients with known OMPF lesions. For example, IED patients do not learn to consistently avoid making choices associated with a high degree of punishment; and they may have impaired recognition of facial expression and a tendency to overinterpret others’ emotions as negative or hostile.

The authors appear to be interested in establishing, from the similarity in neuropsychological deficits between IED and OMPF-lesioned patients, simply that the frontal region contributing to aggression is likely to be the OMPF. But I think the significance of the study is broader. It is easy to see how these other frontal deficits might be additive with impaired impulse control in causing or contributing to anger outbursts, which may thus in a sense be overdetermined neurobiologically. And even in people who have not qualified for a frank IED diagnosis, a lesser degree of similar orbitomedial dysfunction may predispose to an angry temperament.  New Scientist

Here’s the abstract of the journal article, from the Proceedings of the National Academy of Sciences.