In the past few years, the media have carried stories about horrific crimes, such as massacres at universities or parents killing their children. As the stories unfold, it's often revealed that the perpetrators were emotionally or mentally ill. Frequently, they were not receiving treatment for their illnesses.
It's easy to draw the conclusion that people suffering from mental illness are more violent than other people.
But that's simply not the case, says forensic psychologist Eric Elbogen from the University of North Carolina. He recently completed a study using data from 35,000 adults. Initially, the survey recorded whether or not subjects had a diagnosis of severe mental illness, such as schizophrenia or depression. In later interviews, subjects were asked whether they had committed violent acts.
"We found that there was an association between violence and mental disorder," Elbogen says. "It only reached level of significance when severe mental illness was combined with substance abuse and dependence..."
Elbogen says, even when someone with a mental illness abused drugs or alcohol, this combination was not the strongest predictor for violence.
"There were a number of other factors that were even more closely related to future violence," he says. "[Those include] age, sex, parental criminal history, recent divorce and separation, and recent unemployment and being laid off."
Elbogen says the data show that young men were the most likely to commit an act of violence. As a matter of fact, they were 15 times more likely to be violent than someone with a mental illness.
"We're not saying that the data reveal that mental illness is irrelevant to violence risk," Elbogen says."People with mental illness can and do commit violent acts. What the data is saying is that people without mental illness can and do commit violent acts... "
Elbogen emphasizes that the connection between mental illness and violence is not irrelevant, "but it's not as strong as most people think."
Elbogen says he believes that when someone with mental illness does commit a violent act, people erroneously assume the mental illness is to blame. But he says that's too simplistic. He says both the media and individuals need to be willing to explore the more complex social and environmental reasons why people become violent.
His research is published in Archives of General Psychiatry.