- Impulsive murderers more likely to be cognitively impaired than premeditated murderers, study finds
Impulsive murderers more likely to be cognitively impaired than premeditated murderers, study finds
Posted Jul 3, 2013 5:35 AM CDT
By Debra Cassens Weiss
The minds of murderers who kill impulsively, sometimes out of rage, differ from those of premeditated murderers who plan their crimes, according to a Northwestern Medicine neuropsychologist.
Researcher Robert Hanlon administered intelligence and neuropsychological tests to 77 convicted murderers in Illinois and Missouri. A Northwestern University press release highlights his findings:
• Compared to predatory murderers, impulsive murderers are more likely to be developmentally disabled and have cognitive and intellectual impairments—59 percent versus 36 percent.
• Compared to impulsive murderers, premeditated murderers are almost twice as likely to have a history of mood disorders or psychotic disorders—61 percent versus 34 percent.
• Ninety-three percent of the impulsive murderers had a history of alcohol or drug abuse, or were intoxicated at the time of the crime, compared to 76 percent of the premeditated murderers.