Is There a Relationship Between Mental Illness and Homicide?

Many studies that tackled the issue of the relationship between mental illness and homicide have detected mental disorders in many defendants charged with extreme cases of violence.

For example, a study of 71 people convicted of murder (excluding vehicular homicide) in Contra Costa County, California, found 49 of them suffered from serious mental disorders.

Experts study homicide and mental illness
Is there a link between mental illness and homicide?

The diagnoses included multiple infarct dementia, chronic paranoid schizophrenia, antisocial personality disorders, and psychosis linked to drugs like methamphetamine

The study found most people convicted of homicide were not legally incompetent or mentally ill by “common standards.”  However, a high percentage of murderers appeared to be mentally ill.

Other research suggests the California study may overestimate the link between mental illness and homicides.

More recent research carried out into people convicted of homicides in the United Kingdom, found 545 of the 1594 defendants suffered from a mental disorder, amounting to 34 percent. Of these, 149 received a diminished responsibility verdict in which a judge and jury acknowledged the role a mental disorder played in the crime.

Most of the killers who had a mental disorder had not been treated by psychiatric services. This is a theme we see over and over again. People with mental disorders are more likely to commit violent crimes if their condition goes untreated.

Unfortunately, many people with mental illnesses in Arizona do not receive proper treatment for their conditions.

A 2016 report by the Treatment Advocacy Center called Serious Mental Illness and Homicide found people with schizophrenia and bipolar disorders are responsible for about 10 percent of all homicides in the United States. For mass killings, the percentage rises to about 33 percent.

Steven P. Segal of the University of California at Berkeley analyzed homicide rates by states. The academic found state homicide rates rose in states with stricter involuntary treatment policies. It appears to be more difficult to treat those in need of help when they are forced into institutions.

At the Garcia Law Firm, we have worked with mentally ill defendants for years. We are well aware of their needs and factors that make violent crime more likely. We are adept at presenting a full picture to the courts in Arizona. Please contact us today if you loved one has been charged with a violent crime.