Being objective about violence
A recent study of mental illness and crime in
One the one hand, the researchers point out that many studies have focused on the relative risk of violence in mental illness – the risk of violence for a person with mental illness as compared to the risk of violence for a non-mentally ill person. They note that focusing on relative risk “gives an incomplete picture” because it does not reflect the “proportion of violent crimes that can be attributed” to the mentally ill. In other words, because the mentally ill comprise such a small percentage of the population (1.4% in
On the other hand, the researchers found that patients with severe mental illnesses were nearly 4 times more likely to have committed at least one violent crime as compared to the general public (6.6% of mentally ill patients had a violence conviction compared with 1.8% of the general population). The study confirms findings in the
Because there is a greater risk that people with mental illness may be violent, it is important for families and caregivers to recognize and have a better understanding of what factors contribute to this risk. For example, a recent CATIE study (see Figure pg. 496) reported that schizophrenia patients experiencing certain positive symptoms (hallucinations, paranoid delusions, and grandiosity) were 9 times more likely to have an episode of serious violent behavior than patients who had negative symptoms (apathy, social withdrawal, poverty of thoughts, blunting of emotions, slowness of movement, and lack of drive). This information is also important in terms of public policy because it supports the need for more timely and effective emergency psychiatric interventions when the most severely mentally ill become symptomatic.
Additional data from the study illustrates why it is important to understand the link between violence and mental illness. In a separate analysis by type of offense, researchers found that patients with severe mental illnesses, who accounted for only 1.4% of the general population, were responsible for 18% of homicides and attempted homicides in