Mentally Ill More Likely to be Victims than Perps

I posted the following on Facebook last week after watching a decontextualized report on the evening new:

I was mildly shocked when an acquaintance from high school questioned this in the comments. I wanted to re-present the research here as I'm sure that many of us find this claim counterintuitive.

First, here are three peer-reviewed journal articles that make this point:

• Lancet: Prevalence and risk of violence against adults with disabilities: a systematic review and meta-analysis of observational studies
  - (coverage from the BBC)
• Lancet: Prevalence and risk of violence against children with disabilities: a systematic review and meta-analysis of observational studies
• Psychiatric Services: Perpetration of violence, violent victimization, and severe mental illness: balancing public health concerns

My friend seemed perplexed by the research since the alleged Aurora gunman was clearly disturbed. I shared that it has been reported that Jared Holmes was receiving psychiatric treatment through the University of Colorado campus where he had been a student, but we do not yet know what his exact diagnosis was. Clearly, he was afflicted with a mental illness. In no way, however, does that refute the claim that the mentally ill are more likely to be the victims than the perpetrators of violence.

Here is an example that I shared to help clarify things. (It's a variation of a heuristic I got from Sociology Focus.) Imagine I am the coach of a football team, and I tell the team that the average maximum bench press for our squad this season is 200 lb. “But, coach,” Billy interjects, “that can’t be correct because I maxed out on the bench at 280 lb.!” Billy’s mistake, while I hope obvious to us, is quite common. We can think about the findings about mental illness in the same way. Yes, some people who are mentally ill do violence to others. On average, though, the overwhelming majority do not. About 1 out of 4 who are mentally ill, however, will be victimized in a given year. We can even quantify that and say that people living with mental illness are 10 times(!) more likely to be victims of violence than perpetrators. We risk a serious logical error if we claim that one individual invalidates what we know literally from thousands of others.

It is easy for us to assume that those who are mentally ill are dangerous when, in reality, they are the ones who are actually endangered in our society. The overriding concern I have based on this science is that mental illness is still highly stigmatized in our society, and that stigma further entrenches that vulnerability of those with mental illness because many of us mistakenly believe that we should fear them instead of being afraid for them.

Aside from the substantive issue at hand, I found the exchanging illuminating. I'll admit, my knee-jerk reaction was to be annoyed with my Facebook friend, but the more I thought about it, the more I realized that this was in fact what I do as an scientist-educator and this was an incredible moment for teaching. In the end, he was convinced by my exposition of the research. I hope that others learned something, too.

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UPDATE (12/17/2012):

Two more articles worth reading:

• New York Times: In Gun Debate, a Misguided Focus on Mental Illness
• The American Journal of Psychiatry: The Population Impact of Severe Mental Illness on Violent Crime

UPDATE (2/15/2018):

• American Journal of Public Health: Mental Illness, Mass Shootings, and the Politics of American Firearms

UPDATE (7/30/2018):

• The Incidental Economist: Becoming mentally ill increases your risk of becoming a crime victim

UPDATE (8/23/2022):

• What Are the Real Warning Signs of a Mass Shooting?