Violence Can’t Always Be Linked to Mental Illness

On April 16, 2007, Seung-Hui Cho, age 32, killed 32 people on the Virginia Tech campus before committing suicide. It was the single deadliest school shooting in US history. Cho was diagnosed with a severe anxiety disorder in childhood and declared mentally ill by a court of law in 2005. Jeffery Dahmer is considered to be one of the worst serial killers in history. He committed acts of murder, rape, and cannibalism upon 17 victims-and those are only the victims of which we are aware. Dahmer was found to be legally sane, but some have suggested he may have been autistic. Ted Bundy was so articulate as his own lawyer that the judge said he would be glad to have him in his courtroom as an attorney. Was he insane? Did he know right from wrong? The unibomber, Ted Kaczynski, was determined to have a severe mental illness, but he was criminally responsible for his actions, The more we learn, the more confusing it gets.

The first thing people want to do is make sure that those with severe mental illnesses cannot get guns. This is a good idea, but doesn’t solve the problem of violent people who do not have a mental illness.

The MacArthur Study of psychiatric inpatients found that mental illness alone is not an accurate predictor of future violence. In fact, the study found, someone who is diagnosed as Schizophrenic is even less likely to be violent than the average person. The study found that the major risk factors for violence are: a childhood history of abuse, prior arrests, antisocial personality disorder, drug abuse by parents, substance abuse, anger control problems, violent fantasies, involuntary commitment to a psychiatric hospital-and even something as simple as being a young male. This is not to say that mental illness and violence are completely unrelated, or that those who are diagnosed as mentally ill do not commit violent acts. However, those people with mental illness who do end up being violent tend to do so when they are off of their medications, avoiding treatment, and/or abusing substances. They also tend to have additional diagnoses on Axis II.

Every day, in order to determine who will have to stay in the hospital involuntarily, mental health professionals have to determine whether a person is an imminent danger to himself or others. The research makes it clear that unaided clinical judgment in predicting future violence is little better than chance. Actuarial tools provide somewhat of an improvement over clinical judgment, but how many hospitals, parole boards, prisons, jails, courts, and police agencies are using them in the US?

Although the use of actuarial tools, such as the PCL-R, VRAG, and STATIC 2000 are already commonplace in Canada-where most of these tools were developed-the trend is only now beginning to work its way into common US mental health and criminal justice practices. It needs to be universal. We cannot continue to let dangerous people out on the street because we think they might not be dangerous. That should no longer be our standard of care. Clinical judgment in determining risk of future dangerousness has an almost 50% error rate. Actuarial tools have correct classification rates for dangerousness of 65-80. Our traditional psychological tests cannot be used I this way.

My own research on violence has shown that psychiatric illness and symptomology alone is not sufficient to predict future violence. There is no simple construct. It takes a combination of risk factors and an absence of resiliency factors to predict future violence. We run the risk of being too simplistic when we try to narrow violence down to a single, weakly related factor such as mental illness. If a mentally ill person stops taking his/her medication, has a past assault on another, and begins abusing substances, he/she is at a greater risk for future violence than the mentally ill person without these characteristics. We have a great deal of tools at our disposal that will accurately assess the possibility of future violence, and we know the steps toward managing it. Isn’t it time that we used these tools universally?