Road rage 'a medical disorder'

2006-06-06 15:00

Chicago - To you, that angry, horn-blasting tailgater has road rage. But doctors have another name for it - intermittent explosive disorder - and a new study suggests it is far more common than they realised, affecting up to 16 million Americans.

"People think it's bad behaviour and that you just need an attitude adjustment, but what they don't know ... is that there's a biology and cognitive science to this," said Dr Emil Coccaro, chairperson of psychiatry at the University of Chicago's medical school.

Road rage, temper outbursts that involve throwing or breaking objects and even spousal abuse can sometimes be attributed to the disorder, though not everyone who does those things is afflicted.

By definition, intermittent explosive disorder involves multiple outbursts that are way out of proportion to the situation. These angry outbursts often include threats or aggressive actions and property damage.

The disorder typically first appears in adolescence; in the study, the average age of onset was 14.

The study was based on a national face-to-face survey of 9 282 US adults who answered diagnostic questionnaires in 2001-03.

About five percent to seven percent of the nationally representative sample had had the disorder, which would equal up to 16 million Americans. That is higher than better-known mental illnesses such as schizophrenia and bipolar disorder, Coccaro said.

More common than previously thought

The findings were released on Monday in the June issue of the Archives of General Psychiatry.

The findings show the little-studied disorder is much more common than previously thought, said lead author Ronald Kessler, a health care policy professor at Harvard Medical School.

"It is news to a lot of people even who are specialists in mental health services that such a large proportion of the population has these clinically significant anger attacks," Kessler said.

Four a couple of decades, intermittent explosive disorder, or IED, has been included in the manual psychiatrists use to diagnose mental illness, though with slightly different names and criteria.

That has contributed to misunderstanding and underappreciation of the disorder, said Coccaro, a study co-author.

Coccaro said the disorder involves inadequate production or functioning of serotonin, a mood-regulating and behaviour-inhibiting brain chemical.

Treatment with anti-depressants, including those that target serotonin receptors in the brain, is often helpful, along with behaviour therapy akin to anger management, Coccaro said.

"This is a well-designed, large-scale, face-to-face study with interesting and useful results," said Dr David Fassler, a psychiatry professor at the University of Vermont.

On the net:

www.archgenpsychiatry.com

- AP