News Release

Some domestic abusers may have faulty mechanism for controlling aggression

Peer-Reviewed Publication

Center for Advancing Health

Some perpetrators of domestic violence may suffer from a nervous system irregularity that makes it harder for them to control emotions and aggression, suggest the results of a study.

These findings, if validated by other studies, may increase understanding of the complex phenomenon of domestic violence but can’t explain it in full, according to lead study author John C. Umhau, of the National Institute on Alcohol Abuse and Alcoholism.

"It is important to emphasize that domestic violence is the culmination of a complex set of interactions between the perpetrator, the victim, the environmental circumstances and cultural mores in which the violence takes place," Umhau says.

Domestic violence occurs worldwide and has vast social and medical consequences. "In the United States, an estimated 30 percent of all women who are murdered are killed by their husbands, boyfriends or ex-partners," according to the study’s authors.

The study results are published in the current issue of the journal Psychophysiology.

When perpetrators become violent, they often exhibit extreme responses to environmental stimuli, such as heart palpitations, breathlessness, trembling of the voice and body, flushing and sweating. These symptoms stem from the autonomic nervous system -- the part of the nervous system generally not under conscious control.

Umhau and colleagues focused their analysis on two measures of the autonomic nervous system: heart rate and vagal nerve activity, which is one of several heart rate regulators. Generally, increases in heart rate correlate with decreases in vagal nerve activity. "The vagus responds rapidly to changing metabolic demands, whether from agitated emotional arousal or from a simple posture change, and immediately adjusts heart rate," says Umhau.

Study participants consisted of 16 domestic violence perpetrators recruited through a newspaper advertisement, as well as two comparison groups of 13 nonviolent alcoholics and 15 healthy volunteers. The perpetrators underwent tests to rule out central nervous system damage or brain disorders such as schizophrenia.

All study participants were asked to complete a simple task: to go from bed rest to standing quietly by their bedside for five minutes. The act of standing up is a natural physiological stressor that raises heart rate. Umhau and colleagues monitored the study participants' heart rate and vagal nerve activity on a minute-by-minute basis as they stood beside their beds.

After five minutes of standing, all the study participants exhibited a significant increase in heart rate and a decrease in vagal nerve activity. But the groups differed in the minute-by-minute comparison of heart rate and vagal nerve activity. In the healthy volunteers -- but not in the violence perpetrators -- minute-by-minute changes in vagal nerve activity predicted changes in heart rate.

As with the healthy volunteers, the nonviolent alcoholic group showed a correlation between decreases in vagal nerve activity and increases in heart rate, but this correlation did not reach statistical significance.

Umhau and colleagues speculate that the faulty regulation they observed in the heart rates of the violent study participants may also exist in other body parts involved in the expression of emotion and rage, such as the larynx, pharynx, esophagus and bronchi.

"Future studies may confirm that altered heart rate regulation provides a measurable index of autonomic dysregulation, which, in turn, may be found to affect the perpetrators' ability to modulate emotion and to control aggression," Umhau says.

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Psychophysiology is the official peer-reviewed journal of the Society for Psychophysiological Research. For information about the journal, contact Gregory A. Miller, Ph.D., at (217) 333-6312.


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