(Aug. 27, 2015) Severe mental illness was found to be more prevalent among people who murdered family members or intimate partners than those who killed strangers, according to a new study published in the Journal of Forensic Sciences (“The killer in your home: Domestic-violence researcher works up a profile,” Chicago Tribune, Aug. 25).
The Northwestern University study examined the demographics and psychiatric history of individuals who had murdered relatives or close others and compared them with those who had murdered strangers.
Researchers spent more than 1,500 hours interviewing and personally evaluating 153 murderers. Participants were women and men charged with and/or convicted of first-degree murder in Arizona, Colorado, Illinois, Indiana, and Missouri.
They found that those who killed loved ones have a different psychological profile than those who killed unknowns, including a higher likelihood of psychotic disorders.
Hanlon cautions that mental illness alone is not necessarily a sign of potential violence.
"But if you have someone who does have a severe mental illness who, most importantly, has a history of violence against others, then those are two big factors that need to be taken into consideration," Hanlon said.
The finding of the study could have enormous implications for family members of those living with a severe mental illness.
“These crimes are often preventable if family members are more informed about the potential danger from having someone who is severely mentally ill in the home and who may have shown violent tendencies in the past,” the authors said.
Indeed, individuals with a history of mental illness (not including drug or alcohol abuse) are responsible for approximately 25 percent of homicides in the United States in which an individual his or her parent, according to a Department of Justice study.
The recent tragedy in which Oklahoma Labor Commissioner Mark Costello was stabbed to death by his son during a psychotic break serves as an example of the sometimes dangerous interaction between those with untreated serious mental illness and their families.
Read the Treatment Advocacy Center backgrounder “What percentage of homicides are attributable to individuals with serious mental illness” to learn more.
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