June 29, 2013
Premeditated Killers Differ Mentally From Impulsive Murderers
redOrbit Staff & Wire Reports - Your Universe Online
The minds of premeditated murderers are quite different than those who kill impulsively, according to a new study appearing in the latest edition of the journal Criminal Justice and Behavior.
"Impulsive murderers were much more mentally impaired, particularly cognitively impaired, in terms of both their intelligence and other cognitive functions," said Dr. Robert Hanlon, senior author of the study and an associate professor of clinical psychiatry and clinical neurology at the Northwestern University Feinberg School of Medicine.
Murderers whose acts are predatory and premeditated in nature did not typically demonstrate any type of cognitive or intellectual dysfunction, but were more likely to have psychiatric disorders, Dr. Hanlon added.
As part of his research, he studied 77 murderers incarcerated either in the state of Illinois or the state of Missouri. Each of them took standardized intelligence and neuropsychological memory tests.
Compared to impulsive killers, premeditated murderers were nearly twice as likely (61 percent versus 34 percent) to have a history of psychotic or mood disorders, while impulsive murderers were more likely (59 percent versus 36 percent) to have developmental disabilities and cognitive/intellectual impairments, the study claims.
Nearly all of the impulsive murderers have a history of alcohol or drug abuse and/or were intoxicated at the time of the crime -- 93 percent versus 76 percent of those who strategized about their crimes.
The study is "the first to examine the neuropsychological and intellectual differences of murderers who kill impulsively and those who kill as the result of a premeditated strategic plan," said Sarah Griffiths of the Daily Mail.
According to The Telegraph's Radhika Sanghani, Dr. Hanlon is calling on lawmakers to take intelligence and the mindset of murderers into consideration both in terms of prosecution and crime prevention.
"It's important to try to learn as much as we can about the thought patterns and the psychopathology, neuropathology and mental disorders that tend to characterize the types of people committing these crimes," the study author explained.
"Ultimately, we may be able to increase our rates of prevention and also assist the courts, particularly helping judges and juries be more informed about the minds and the mental abnormalities of the people who commit these violent crimes," he added.