CHICAGO --- Murderers who kill intimate partners and family members have a significantly different psychological and forensic profile from murderers who kill people they don’t know, reports a new Northwestern Medicine study that examined the demographics, psychiatric history and neuropsychology of these individuals. 
 
 The new knowledge about murderers who commit what is called spontaneous domestic homicide -- emotionally driven crimes that are not premeditated -- could enable early intervention to prevent the homicide, the authors said. 
 
 Domestic homicide is one of the most common and frequent types of murder in the U.S. 
 
 One-third of all women murdered in the U.S. are killed by their male partners including husbands, ex-husbands, boyfriends and ex-boyfriends. An estimated 25 percent of women will be victims of severe domestic violence by an intimate partner in their lifetimes. 
 
 “The findings provide important information that may help prevent future domestic homicides, because they help identify individuals at risk of committing domestic murders,” said lead author Robert Hanlon, director of the forensic psychology research lab at Northwestern University Feinberg School of Medicine. “The killers in this group are very similar to each other and different from men who commit nondomestic murders, which are often premeditated.” 
 
 Hanlon also is an associate professor of psychiatry and behavioral sciences at Feinberg and a neuropsychologist at Northwestern Memorial Hospital. 
 
 The study on spontaneous domestic homicides found these killers have more severe mental illness (particularly psychotic disorders), few previous felony convictions, are less intelligent and have more cognitive impairment. The paper was published Aug. 21 in the early view online edition of the Journal of Forensic Sciences. 
 
 “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,” Hanlon said. “Family members may lull themselves into a state of false beliefs thinking ‘my son would never hurt me’ or ‘my husband may have a short fuse but he would never seriously harm me.’” 
 
 “The fact is the husband or son may very well harm the wife or mother,” Hanlon said. 
 
 These murders are not a premeditated, strategic type of killing, noted Hanlon, who testified in the James Holmes Colorado theater mass murder trial in Denver in July. 
 
 “These murders are in the heat of passion and generally involve drugs or alcohol and often are driven by jealousy or revenge following a separation or a split,” Hanlon said. “This is grabbing the kitchen knife out of the drawer in a fit of anger and stabbing her 42 times.” 
 
 Another scenario is a murder committed by a mentally ill son or another family member who is psychotic and thinks the victim is plotting against him. 
 
 Intimate partners and family members need to notify the authorities that they are concerned about potential harm and remove themselves from the situation, Hanlon recommended. 
 
 “You can stay with relatives, call domestic violence hotlines and say, ‘I’m scared something is going to happen to me,’” Hanlon said. “Start the wheels turning and get assistance.” 
 
 For the study, Hanlon interviewed and personally evaluated 153 murderers for more than 1,500 hours. Participants were men and women charged with and/or convicted of first-degree murder in Illinois, Missouri, Indiana, Colorado and Arizona. 
 
 “You learn a lot about them in that amount of time,” Hanlon said. “I saw the same patterns and trends over and over again.” 
 
 Hanlon is the author of “Survived by One: The Life and Mind of a Family Mass Murderer (2013).” ||||| Men who murder those they know have a different psychological profile from those who kill strangers, according to a new study. 
 
 The Northwestern University report released today studied the demographics and psychiatric history of people who killed partners or family members. 
 
 The study, conducted by evaluating 153 killers for more than 1,500 hours, found that those who killed people close to them shared a string of qualities. 
 
 These murderers often had severe mental illness, cognitive impairment and lower IQ scores. They also were less likely to have prior felony convictions than those killing strangers, according to the data. 
 
 "They were less intelligent, more cognitively impaired, and they tend to have poor emotional control and impulsive tendencies," said author Dr. Robert Hanlon, director of Northwestern University Feinberg School of Medicine's forensic psychology research lab. "Clearly, it was those kinds of cognitive and behavioral tendencies that resulted in them committing the crimes." 
 
 Researchers hope that by studying emotionally driven crimes, data will point to ways to intervene. 
 
 Hanlon said some results of the study surprised even him — such as domestic homicides being less likely to include guns as the murder weapon. Only 14 percent of those who committed a spontaneous domestic homicide used a gun, versus 59 percent of nondomestic homicides. 
 
 "That was a bit of a surprise," he said. "It's what is the instrument that is available, like the butcher knife from the kitchen or strangulation, or beatings, rather than going and finding the gun and loading the gun." 
 
 Those killing partners or relatives had twice the rate of psychotic disorders, according to the data. Nearly half (46 percent) of criminals surveyed had a psychiatric diagnosis, from schizophrenia to psychic disorders. 
 
 "These kinds of similarities did stand out in them," said Hanlon, also author of "Survived by One: The Life and Mind of a Family Mass Murderer." 
 
 Unlike premeditated, strategic killings, these often happen in the heat of passion, fueled by drugs, alcohol, jealousy, revenge or a toxic mix of all these, the report said. 
 
 Psychological problems play a role — a mentally ill son or partner, for instance, might think the victim is plotting against him. 
 
 Those surveyed, and interviewed and evaluated by Hanlon, were charged or convicted of first-degree murder in Illinois, Missouri, Indiana, Colorado and Arizona. More than 70 percent of participants were criminal defendants in the Cook County Department of Corrections. 
 
 Among the 263 total victims in the cases, murder weapons included guns, knives, bats, hammers, clubs, rocks and fists. 
 
 In Chicago alone, recent examples abound of men killing women they knew. Just last week, police said, a man walked into AmeriCash Loans in the Loop and shot his ex-girlfriend, who was a clerk. In April, a man was charged with fatally shooting his ex-girlfriend in front of her two children. Last year, a woman was shot on her 22nd birthday by her ex-boyfriend, who then killed himself, at the Nordstrom on Michigan Avenue. 
 
 In a startling statistic, the report notes that one-third of murdered U.S. women are killed by partners — husbands, ex-husbands, boyfriends and ex-boyfriends. 
 
 And about 25 percent of women will be a victim of severe domestic violence during their lifetimes. 
 
 Signs of shared, potentially lethal qualities that could signal a red flag include a history of violence and severe psychological problems. Also, Hanlon advised considering potential stressors and whether someone is taking medication prescribed for a mental illness. 
 
 Hanlon cautioned that mental illness alone is certainly not 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," he said. 
 
 Women often assume — wrongly, Hanlon said — that a son, boyfriend, husband or ex could never be in this category, thinking, "My husband may have a short fuse, but he would never seriously harm me." 
 
 "Everyone wants to feel comfortable in their own home, and they don't want to accept and believe that they're at risk, particularly by a family member who, in many cases, they love or loved at one time," he said. "To then accept and believe that this person may seriously harm me or may kill me, that's a very difficult concept." 
 
 abowen@chicagotribune.com 
 
 Twitter @byalisonbowen
– The kind of man who kills his wife or family fits a pattern, and this new understanding of who commits this kind of murder could help prevent them from happening in the first place. So report Northwestern University researchers in the Journal of Forensic Sciences after interviewing and evaluating 153 murderers for more than 1,500 hours. Domestic homicide is one of the most common types of murder in the US, with one-third of all murdered American women killed at the hands of their male partners, current or former. Among the things these killers have in common? Severe mental illness—especially psychotic disorders—along with few previous felony convictions, lower intelligence, low emotional and impulse control, and greater cognitive impairment. "These murders are in the heat of passion and generally involve drugs or alcohol and often are driven by jealousy or revenge following a separation or a split," lead researcher Robert Hanlon says. "This is grabbing the kitchen knife out of the drawer in a fit of anger and stabbing her 42 times." In fact, guns are the murder weapon in only 14% of these cases; knives, bats, hammers, clubs, rocks, and fists were other weapons used by the men interviewed, reports the Chicago Tribune. "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," Hanlon adds. "The fact is the husband or son may very well harm the wife or mother." (The man who recently murdered six kids and their parents in Houston was an estranged boyfriend.)