Deadly patterns revealed in killers’ minds

IMPULSIVE murderers are more likely to have impaired brainpower or disabilities than premeditated murderers, scientists say.

And strategic killers are almost twice as likely to have a psychological disorder as spontaneous murderers, according to a study in the journal Criminal Justice and Behaviour. It compared 77 murderers in prisons in the US and found that their intelligence and the nature of their crimes followed a distinct pattern.

Of the impulsive murderers 59% were impaired mentally, compared with the 36% of strategic killers who were intellectually challenged.

More than nine in 10 impulsive murders involved substance abuse or the murderers had a history of drug use or alcohol addiction.

Dr Robert Hanlon, a professor of clinical psychiatry and clinical neurology at Northwestern University, Illinois, who carried out the investigation, said: “Impulsive murderers were much more mentally impaired, particularly cognitively impaired, in terms of both their intelligence and other cognitive functions. “The predatory and premeditated murderers did not typically show any major intellectual or cognitive impairments, but many more of them have psychiatric disorders.”

Hanlon found that 61% of killers who spent time planning their homicides had a history of psychotic or mood disorders, whereas only 34% of those who murdered in the heat of the moment had similar issues.

Hanlon has called for lawmakers to consider the intelligence and mindset of killers closely in prosecution and for crime prevention.

“Ultimately, we may be able to increase our rates of prevention and also assist the courts, particularly helping judges and juries to be more informed about the minds and the mental abnormalities of the people who commit these violent crimes.” — © The Daily Telegraph, London