Random shooting of strangers in public spaces by a lone gunman might dominate the headlines, but, (anti-gun-control lobby in the USA please note) other kinds of mass killing are actually more common. Disaffected employees who return to shoot the boss and co-workers after being sacked, alienated husbands who slay entire families before turning the gun on themselves, robbers who wipe out witnesses, and racists who target immigrants, are all more frequent statistically.
Yet perhaps because of the very apparent meaninglessness of the random slayings, these always get much more media attention. However, even amongst the mindlessness, patterns are emerging.
James Alan Fox, a Professor of Criminal Justice, and Jack Levin, Professor of Sociology & Criminology, both at Northeastern University, Boston came up with one of the most definitive typologies of the phenomenon.
Their first type is the 'power-oriented' mass killer - these 'pseudo-commandos' boast battle fatigues and symbols of power such as assault weapons, being motivated by dominance and control. Then there is the 'revenge' type - seeking to get even, either with those he knows, or those who represent others who have humiliated him (in his opinion). Meanwhile the 'terror' type intends to "send a message" through their murderous rampage. These different categories can and often do overlap.
Psychologist Dr Peter Langman, author of the book Why Kids Kill - Inside the Minds of School Shooters proposes an alternative classification which may also be especially relevant to recent cases in the headlines. This emphasises instead that a significant number of these mass killers, particularly if they are in their late teens or early twenties - which is a peak age for the onset of psychosis in men - might be suffering from a range of psychotic illnesses. Langman for example argues that Seung Hui Cho whose rampage at Virginia Tech in 2007 killed 32 and wounded 17, might be typical of this type.
Langman reports that after Seung Hui Cho arrived at college, the so-called 'negative' symptoms of
schizophrenia, including poverty of speech and ﬂattened emotional responsiveness, became more prominent. Many don't realise that psychotic illnesses like schizophrenia are not just diagnosed from hallucinations and delusions, but also 'negative' symptoms such as withdrawal and isolation. Towards the end, Seung apparently barely spoke.
In his recent research paper entitled 'Rampage school shooters: A typology' published in the academic journal, 'Aggression and Violent Behaviour', Langman suggests that, with the benefit of hindsight, delusional thinking may now be recognisable. Seung Hui Cho claimed to have a supermodel from outer space as a girlfriend. Langman reports that on occasions he told roommates she was in their dorm room. He also apparently claimed an association with Russian leader Vladimir Putin, plus he seems to have compared himself to Moses, believing he was leading a mass movement and would be remembered as a great leader. His paranoia was evidenced in claims that others were trying to kill him, Langman contends. Possibly believing he was on the verge of annihilation, his attack appears to have been a response to beliefs of widespread attempts to destroy him.
Langman's analysis of recent mass killings in schools and colleges in the USA leads him to conclude that half of these shooters had what he terms 'schizophrenia-spectrum' disorders. Langman acknowledges that this high prevalence of psychosis has not been suggested so strongly before.
He defends his finding however by pointing out that evidence of psychosis may not emerge until months or years after the slaying. In the case of Dylan Klebold, for example, his journal was not released until seven years after the attack at Columbine. Attempts to investigate this killer could not access this crucial information before.
Eric Harris and Dylan Klebold were responsible for the Columbine School massacre, killing 13 and wounded 23 in Jefferson County, Colorado in 1999. Klebold's journal suggests, according to Langman, he didn't think he was human, at times believed he was God, and disturbed thought processes may be revealed by his tendency to create new words - referred to as 'neologisms' in psychiatry.
Intriguingly in the case of Anders Breivik, the Norwegian mass killer, the first two court-appointed psychiatrists who examined him were also interested that Breivik might be using neologisms, and this may have contributed to them diagnosing him as possibly psychotic.
There are many who will be furious at the attempt to diagnose mass killers, believing this is a way of them 'getting off' or of eluding responsibility. But since the vast majority of those diagnosed with any psychiatric disorder are not violent, personal responsibility probably still has a role to play, even if psychotic processes can be found in these killers. A diagnosis or a psychological analysis doesn't mean a court cannot find these perpetrators guilty, and sentence them to prison. Being sent to a secure hospital doesn't signal imminent release either.
Also improved understanding of the possible psychological processes in play, if made more widely available to the public, means it just might be possible for others to notice some of the earliest signs of incipient disorder, to see when they start to act strangely, to become more aware of when they are lacking something. If we understand the development of this kind of mindset better, in future, we might just be a bit better at predicting and preventing some of these catastrophes.
Another reason it's vital that we attempt to get to the bottom of these processes psychologically is this could enable us to prevent these dreadful crimes by an additional method.
Paul Mullen, Christopher Cantor and colleagues have published an analysis of possible copy cat mass slayings where they argue the influence of one rampage on another may have occurred across continents, and even over many years.
Their study entitled 'Media and Mass Homicides' published in the journal Archives of Suicide Research tracked seven mass homicide incidents occurring in Australia, New Zealand and the UK between 1987-1996. They found a complex web of multiple influences between the different incidents on the perpetrators, especially influenced by the colossal media coverage each tragedy received.
For example the perpetrator of a mass killing in Port Arthur Australia in 1996, where 35 people were slain, might have been influenced not just by the Dunblane tragedy in Scotland, where 16 children were killed just 46 days before, but also two mass killings in Melbourne, almost 10 years previously.
Mullen and colleagues point out that following research evidence that press coverage of suicides leads to copy cat suicides in the general population, there are now media guidelines discouraging certain kinds of reporting. Their research suggests the same guidance and restrictions should now apply to media reporting of mass killings. Of all kinds of mass murder, this type might be the most sensitive to and encouraged by media coverage.
It's beginning to look like such blanket and graphic reporting is in fact encouraging some of the disturbed and disaffected all over the world to try their own hand at infamy, and a warped sense of power.
Follow Dr Raj Persaud on Twitter: www.twitter.com/@DrRajPersaud