According to an American academic, when you witness road rage (even in yourself) you may be observing a psychiatric condition called intermittent explosive disorder that many people don't know is a mental illness.
The same goes for spouse abuse, or any other angry outburst where the emotional intensity goes well beyond the situation at hand.
Ronald Kessler, a professor of health care policy at Harvard Medical School, conducted the study and found, to his surprise, that 7.3 per cent of adults interviewed had experienced this kind of unbridled anger. "The acts are out of proportion to the social stressors triggering them," prof Kessler said. The study appears in the latest issue of the Archives of General Psychiatry.
That percentage translates into 16 million Americans. On an annual basis, Kessler estimates that 8.4 million Americans rage, and their behaviour can go from threatening people to hurting them or breaking objects.
While many of the 9,282 adults interviewed said they never considered these angry outbursts a psychiatric problem, the scientists found that 82 per cent of them also had received a diagnosis of depression, anxiety or alcohol or drug abuse at some point in their adult life.
But what prof Kessler and his colleagues found most interesting was that the angry outbursts appeared well before these other psychiatric conditions.
"Intermittent explosive disorder may be a risk factor for other mental disorders," prof Kessler said. "If identified early in life, and treated, perhaps we can avoid some of these other psychiatric problems that emerge in adulthood."
Prof Kessler said the anger issues never came up during treatment for depression and anxiety. "The patient comes in saying he is sad, not angry," Kessler said. "So it's not on the therapist's radar screen."
"Telling people that this has a name, and a treatment, is critical," he added.
Dr Emil Coccaro of the University of Chicago, a co-investigator in the study and an expert on explosive behaviour, said that this psychiatric condition "is a serious biomedical problem that can be treated."
So who fits the diagnosis? According to Kessler, a person must have at least three major episodes of extreme impulsive aggression throughout their life to loosely qualify for the condition.
The outbursts are sudden and violent, with physical injury or damage to property. Most of the people identified admitted sending people to the hospital. On average, the first outburst occurred around age 13 for males and 19 for females.