What causes someone to do a mass shooting? – Mental Health Matters
Every day in America, there are thousands of individual acts of violence, some “random,” others not. In places the violence is so common, so “ordinary,” that few, aside from the police and grieving family, seem to notice.
Sometimes the violence catches the media’s attention, particularly if the victim is a public figure, a”star” of some sort, or if the violent act is particularly gruesome or bizarre. Almost invariably, when the media pay attention, there is a focus on the mental stability of the violent actor.
People tend to believe violence that is not state-sanctioned stems from mental illness, that only a “crazy” person would severely injury or kill another human being. In one 2013 study, nearly half of the survey sample said that people with a mental illness are more dangerous.
The facts are more complex and nuanced, and it’s only by understanding them that we can construct sane public policy.
First, there’s the remarkable financial cost of interpersonal violence. The World Health Organization notes that the cost of interpersonal violence in the United States is more than $300 billion per year. The cost to victims is estimated at $500 billion. Overall, the numbers reach an astounding 10 percent of the Gross Domestic Product.
Research indicates the level of violence among those with a major metal illness who do not abuse substances is either no different or only slightly more than the general population.
The National Epidemiological Survey on Alcohol and Related Conditions states that of more than 30,000 people found, less than 3 percent of people with severe mental illness acted violently during the past year, compared to 1 percent of the general population.
A relevant difference, yes, but the key finding is that some 97 percent of those with severe mental illness were not violent.
Still, there are distinctions that matter. According to a 2009 review, schizophrenic people are twice as likely to be violent; 35 percent of schizophrenic people commit a violent act at some point during their lives. Moreover, 5-10 percent of all murders are committed by people with mental illness.
But mental illness alone is a far less relevant causative factor than others. Virtually all the research demonstrates that substance abuse, particularly alcohol abuse, is far more predictive of violence than mental illness. Substance abuse in a person with mental illness more than triples the risk of violence.
Another way of digesting the data: Violence would be reduced by 33 percent if we could magically eliminate substance abuse, but by just 5 percent if we could eliminate mental illness.
So, the vast majority of violence has no direct relationship to mental illness.
There are other much better predictors of violence than mental illness.
One factor, though no one has found a way to eliminate it, is maleness; 90 percent of murders are committed by men, and 80 percent of murder victims are men. Moreover, the vast majority of violent acts are committed by men between the ages of 18 and 30.
Youth is a factor in predicting homicide, particularly in the United States where the youth homicide rate is more than 10 times that of nations like Germany, France and the United Kingdom.
Actually, and this has policy implications we’ll consider momentarily, the single best predictor of violence is a past history of violence.
Another predictor, though less so, is poverty — not just the fact of poverty, but poverty in relationship to wealth.
Research reported in Scientific American indicates that a major contributor to homicide in the United States is economic disparity; the wider the disparity between rich and poor, the more the violence. Less disparity between those at the bottom and those at the top financially correlates with lower levels of violence.
This study, and others, notes that violence occurs in a social context and cannot be predicted solely by identifying characteristics of the violence prone individual.
For example, the mentally ill who are violent direct their aggression against family members or friends nearly 90 percent of the time, typically in the home. Random acts of street violence committed by the mentally ill are actually rare events. Indeed, mental patients discharged from a hospital are less likely to target strangers than is the general population.
There is one major exception to the low potential for violence in the mentally ill, and we saw yet another example of it in Oregon two weeks ago; perpetrators of mass shootings very frequently have a history of mental illness.
So what are some of the implications of this data?
For one, the availability of lethal weapons should be restricted for the population with a history of violent behavior. A history of alcohol and/or substance abuse should lead to similar restrictions as should a history of legal mental health commitment or chronic and severe mental illness.
Also, improved access to mental health and substance abuse treatment resources will decrease violent behavior.
In the end, devoting more of societies resources to the prevention of violence will matter.
The mass shootings in Oregon provide a policy opening, but politicians must have the courage to walk through it. And we need to have the wisdom to push them there.
Incline Village resident Andrew Whyman, MD, is a clinical and forensic psychiatrist. He can be reached for comment at firstname.lastname@example.org.
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