We all get angry sometimes. Some of us, no doubt, are angry right now. Some of us are angry for wholly legitimate reasons to do with a computer that has been temporarily inhabited by evil spirits, and some of us are just being irrational. And some of us, it seems, have anger as a disease.
A study carried out by researchers from Harvard Medical School and the University of Chicago shows that as many as 16 million Americans may suffer from a form of anger called intermittent explosive disorder, a condition characterised by "a failure to resist aggressive impulses".
When does an emotion become a disorder? What is the difference between an anger syndrome and plain old anger? For many critics of the increasing trend toward the "medicalisation" of everyday problems, a brand new anger disease seems like another way of devolving responsibility for one's bad behaviour. In America, you may not be surprised to hear, intermittent explosive disorder has been used successfully as a legal defence.
According to Dr Deenesh Khoosal, spokesman for the Royal College of Psychiatrists here in the UK, such criticisms are wide of the mark. Even if you are diagnosed with IED, he says, "There's still a responsibility to do something about it. If somebody is clearly behaving in this way as a result of this disorder, there is no tablet, pill or potion that's going to stop it. And even if there were, there would be the responsibility for them to take it."
In fact IED, despite its obvious superficial similarities to what used to be called losing one's temper, is a widely recognised condition first added to the American Psychiatric Association's Diagnostic and Statistic Manual of Mental Disorders (DSM) in 1980. It is classified as an "impulse-control disorder" alongside kleptomania, pyromania and trichotillomania (pulling out your hair). "If people think these explosive outbursts are just bad behaviour," says Dr Emil Coccaro, a co-author of the Harvard study, "they are not thinking of this as a serious biomedical problem that can be treated."
IED is precisely defined. It involves "several discrete episodes of failure to resist aggressive impulses that result in serious acts of assault or destruction of property", and "the degree of aggressiveness expressed during the episodes is grossly out of proportion to any precipitating psychosocial stressors". This description appears to encompass such common societal ills as road rage, air rage, trolley rage and phone rage, incidents that are often unhelpfully characterised as understandable responses triggered by the increasing pressures of modern life, rather than over-the-top reactions to ordinary inconveniences.
The Harvard study estimated that IED sufferers commit an average of 43 such outbursts over a lifetime, resulting in $1,359 (£730) of property damage. If the first figure is disturbingly high, the latter seems strangely low, about the cost of one defenestrated widescreen television. Are people taking out their anger exclusively on cheap Ikea furniture?
The study's major finding was that up to 7.3% of Americans surveyed had experienced IED in some form, a much higher number than previous studies indicated, leading to the conclusion that IED, once considered a comparatively rare disorder, is vastly under- diagnosed. Are people getting angrier?
The increase may have more to do with the disorder's complex definition. Before IED can be diagnosed, it is necessary to rule out the possibility that the aggressive episodes are caused by another disorder. IED, it seems, is in large part defined by what it is not. "People can lose the plot and explode for a variety of reasons," says Khoosal. "It could be because they're under the influence of alcohol or drugs, or it could be part of other conditions, such as an explosive personality disorder, Tourette's syndrome or attention deficit disorder, which you get in children. Those things have to be excluded before this particular diagnosis can be made."
The definition has also changed a bit over the years. The DSM once insisted that IED could not be diagnosed in patients with "generalised aggression or impulsivity" but this requirement was dropped from the most recent edition, resulting in an instant increase in candidates. Then there is the difficulty of deciding how many episodes, of what severity, may qualify one for an IED diagnosis. The broadest definition used by the Harvard study - the one that resulted in the 7% figure - required just three episodes in a lifetime. How many of us could say we have gone berserk for no good reason less than three times?
If intermittent explosive disorder still sounds like a new name for a very old problem, diagnosing IED may at least prevent sufferers from being diagnosed with something they have not got. Experts have suggested that people with IED are often misdiagnosed as having bi-polar disorder. While drugs or alcohol may themselves be the cause of explosive outbursts of rage, substance abuse can also be part of an IED sufferer's attempt at self-medication. The Harvard study revealed that while 60% of people with IED had been treated for emotional problems or substance abuse, less than a third had received treatment for their anger.
The symptoms of IED may be apparent, but the causes are little understood. It has been linked to temporal lobe epilepsy, or decreased levels of serotonin, and is thus sometimes treated with anti-depressants. Cognitive therapy is another option. Sufferers, says Khoosal, must learn "how to detect the early stages of development of this explosion, and then to manage it in a way that does not necessarily result in the same outcome. It's too early at this stage to put your money into management with anti-depressants ... do we necessarily have to start medicating people straight away?"
The study also showed that IED commonly makes its first appearance around the age of 14, which may indicate that certain environmental factors, such as bullying, may contribute to it.
The IED study only tells us about anger in America, of course, but if applied directly to the UK population the 7% finding would translate to 4.2 million sufferers. Interestingly, however, Khoosal thinks that certain cultural barriers to exhibiting rage may mean Britain has a lower rate of IED than the US. "In the States the explosions seem to be better tolerated than they are in Britain," he says. "Of course it's more dangerous in America, because everyone's got a gun. Whereas in Britain, I think we're more accustomed to keeping our emotions private rather than public. So you don't often see people having a row with someone who's jumped a queue."
A visit to any supermarket on any Saturday will provide sufficient evidence to indicate that Khoosal is talking about a social construct that is rapidly eroding. People of Britain, it is time to count to 10.