The files of three hundred and ten male offenders serving at least two years in a Canadian prison between 1995 and 1997 were examined for in the study, and of these, 90 were rated as psychopathic according to the Psychopathy Checklist - Revised (PCL-R).

Offenders diagnosed as psychopathic had committed significantly more offences (both violent and non-violent), and psychopathic child molesters had far more charges/ convictions than low-psychopathy offenders.
Offenders classed as psychopathic were around 2.5 times more likely to have been given a conditional release than undiagnosed offenders; psychopathic sex offenders were 2.43 times more likely to have been released than their non-psychopathic counterparts, while psychopathic non sex offenders were 2.79 times more likely to have been released than non psychopathic counterparts.

Dr Porter said: "This is an alarming trend. Psychopathic offenders are far more likely to re-offend, so they should be far less likely to be released. However, we found that psychopathic criminals were in fact highly successful in their bids for freedom."

"This could be because psychopaths were better at manipulating their words and actions, and do this to impress and deceive decision makers throughout the correctional system. Using superficial charm and crocodile tears they may be better able to persuade mental health professionals in prison, and eventually parole boards, that they can be successfully managed into the community."

An alternative explanation put forward by the researchers is that offenders diagnosed with psychopathy appear to make genuine gains in treatment during their prison sentence and positive evaluations in treatment are reflected in the parole board’s decision making. However, Porter argues the appearance of good treatment response in psychopaths is false and they quickly violate their release conditions or re-offend when they return to the community.

"We suggest that professionals who manage offenders in institutions and those charged with releasing offenders back into the community should receive specialised training into the manipulative techniques used by psychopathic offenders to prevent this worrying trend from continuing," continued Dr Porter.

"Although knowledge surrounding the psychopathic personality is more widespread in the correctional system now than when this study was carried out, we still see many examples of psychopaths manipulating the system."

Source: British Psychological Society (Press Release)