Crime Rates & Mental Illness

Source / Statista, FBI

News outlets

and politicians are filling our Twitter timelines and Facebook pages with rhetoric about violent crime and mental health, so it is important to gather some facts. Where there is not hard statistics, there is correlating data. Correlation does not always equal causation, of course, but it makes for a good starting point nonetheless.

According to

the National Alliance on Mental Illness (NAMI), approximately 1 in 5 (46.6 million) adults in the United States experiences a mental illness in a given year. Approximately 1 in 25 adults in the U.S. (11.2 million) experiences a serious mental illness that hinders one or more major life activities in a given year. Employment and education are two of these life activities, for example.

A BMJ study

illustrates that there is some correlation between a rather severe diagnosis such as schizophrenia and a propensity toward violence. Their research shows that 10% of mentally ill patients diagnosed with schizophrenia were found to be more prone to violence, while less than 2% of the general public were found to be prone to violence, by comparison.

When weighed against

a one year population attributable risk, however, mental illness only accounts for 4% of violent crime. This lays the responsibility of violent crime at the feet of the remaining 96% of the general population. People with a mental illness like schizophrenia might be 3 to 5 times more likely to commit a violent crime, but this is similar to correlations that suggest men generally commit more violent crimes than women.

The rates at which

people diagnosed with a mental illness are victims of a crime is perhaps more alarming. Data suggests that the mentally ill are anywhere from 2.5 to 11 times (averaged to about 7 times) more likely to be the victim of a violent crime. Similar studies suggest that people living with mental illness are 15x more likely to be sexually assaulted and 22.5x more likely to be raped.

It is important to consider

the role substance use plays. About 1 in 4 adults living with mental illness also has a substance use issue. This may suggest correlation, but does not necessarily suggest one directly causes the other. This does indicate, however, that it is not as simple as people living with mental illness committing random acts of violence, as corporate media and political leaders will sensationalize.

The most interesting piece

of correlating data refers to crime rates since 1990 weighed against those diagnosed with mental illness. The graph at the top of the page shows the rapid decline in violent crime since 1990. NAMI also estimates that about 60% of those adults diagnosed with a mental illness did not receive treatment in the previous year.

If those diagnosed

with a mental illness are inherently dangerous, and more than half are not receiving treatment, violent crime rates should be going up. But they are not. Data indicates that those living with a mental illness are only slightly, if at all, more violent than the rest of the population.