Less than 7.5 percent of crimes committed by people with mental disorders linked to direct symptoms of their illness, according to a new study.
Many mentally ill people get away with murder, literally. However, the findings of a new study say that this may not be entirely fair. The study found that a mere 7.5 percent of crimes committed by mentally ill people can be directly linked to the symptoms of their disorder.
"When we hear about crimes committed by people with mental illness, they tend to be big headline-making crimes so they get stuck in people's heads," said lead researcher Jillian Peterson in a press statement. "The vast majority of people with mental illness are not violent, not criminal and not dangerous."
For the study, researchers analyzed 429 crimes committed by 143 offenders with three major types of mental illness. All participants were asked to complete a two-hour interview about their criminal history and mental health symptoms, covering an average of 15 years.
They found that only 3 percent of the crimes committed were linked to symptoms of major depression, 4 percent to symptoms of schizophrenia disorders and 10 percent to symptoms of bipolar disorder.
Researchers also noted that two thirds of the people who committed crimes related to symptoms of their mental illness also committed crimes that were not related to any mental disorders. These crimes were consequences of many other factors like poverty, unemployment, homelessness and substance abuse.
"Is there a small group of people with mental illness committing crimes again and again because of their symptoms? We didn't find that in this study," Peterson said.
Researchers also went through the offenders' criminal history to help rate crimes based on their association with symptoms of schizophrenia, bipolar disorder or major depression. A crime was rated as mostly unrelated or mostly related to mental illness symptoms if those symptoms contributed to the cause of the crime but weren't solely responsible for it.
When both these groups were combined the percentage of crimes attributed to mental illness symptoms increased from 7.5 percent to 18 percent. Researchers suggest that programs designed to reduce recidivism should also include cognitive-behavioral treatment about criminal thinking, anger management and other behavioral issues along with mental health treatment.
According to the federal Bureau of Justice Statistics, more than 1.2 million people with mental illness are imprisoned in jails or prisons in the United States. People with mental illnesses also are on probation or parole at two to four times the rate for the general population.
The new study was published online in the journal Law and Human Behavior.
