Psychopaths, who are characterized by a lack of empathy and remorse and possess very shallow emotions, may be born with physical abnormalities in their brains that predispose them towards violent crime like murder, rape and assault.

UK scientists at King's College London's Institute of Psychiatry said that the structural differences in psychopathic brains, significantly different than the brains of healthy non-offenders, are distinct even from other violent offenders with anti-social personality disorders (ASPD).

While psychopaths are often described as being superficially charming and extremely intelligent, they are characterized as being indifferent to the other’s rights and societal rules. Besides having no empathy or remorse they are generally regarded as being callous, selfish, dishonest, arrogant, impulsive, irresponsible, aggressive and hedonistic.

“There is a clear behavioral difference amongst those diagnosed with ASPD depending on whether or not they also have psychopathy. We describe those without psychopathy as 'hot-headed' and those with psychopathy as 'cold-hearted',” Lead researcher Dr. Nigel Blackwood said in a statement.

‘Cold-hearted’ psychopathic participants in the experiments began offending at a younger age, engaged in a wider ranger and greater number of criminal behaviors and were less responsive to treatment programs in adulthood, compared to the 'hot-headed' group, according to Blackwood.

Blackwood and his team measured the volume of grey matter in violent male criminals by using magnetic resonance imaging (MRI) scans and found that ‘cold-hearted’ psychopaths had less grey matter in parts of the brain involved in understanding other people’s emotions.

A total of 66 men took part in the study, which included 44 violent male offenders diagnosed with ASPD and 22 health non-offenders. Researchers said that the crimes committed by the offenders included murder, rape, attempted murder and severe bodily harm, and of the 44 criminal participants, 17 had met the diagnosis for psychopathy (ASPD+P) and 27 did not (ASPD-P).

The findings, published May 7 in the Archives of General Psychiatry, revealed that psychopathic criminals displayed significantly reduced grey matter volumes in the anterior rostral prefrontal cortex and temporal poles, areas that are important for understanding other people's emotions and intentions, and are activated when people think about moral behavior, researchers said.

Previous research indicated that damage to these brain areas were also significantly associated with lack of empathy towards others, poor response to dear and distress and a lack of “self-conscious” emotions like guilt or embarrassment.

Researchers noted that while past studies have also shown that psychopathic brains differ physically from healthy brains, the latest study is the first to have examined these differences within a population of violent offenders with anti-social personality disorders.

“We now know that this behavioral difference corresponds to very specific structural brain abnormalities which underpin psychopathic behavior, such as profound deficits in empathizing with the distress of others,” Blackwell explained.

Researchers said that it is crucial for psychologists to identify and diagnose this psychopathic sub-group of violent criminals with brain scans, rather than grouping them together because it has important implications for treatment.

While those with ASPD can be treated with existing therapies, current treatments for psychopaths may be useless, according to researchers.

“Those without the syndrome of psychopathy, and the associated structural brain damage, will benefit from cognitive and behavioral treatments. Optimal treatment for the group of psychopaths is much less clear at this stage,” Blackwell concluded.