PsychopathsPredicting violence among psychopaths no more accurate than tossing a coin

Risk assessment tools used to predict prisoner re-offending are no more accurate than tossing a coin when it comes to psychopaths, according to new research from Queen Mary University of London.

The researchers say the findings — which also show the tools perform at best moderately in those with depression, drug and alcohol dependence, and schizophrenia — have major implications for risk assessment in criminal populations. The study, funded by the National Institute for Health Research (NIHR) under its Program Grants for Applied Research Program, is published in the British Journal of Psychiatry.

They warn that clinicians carrying out such classifications must be aware of these limitations and ensure prisoners undergo comprehensive psychiatric diagnosis ahead of any risk assessment.

As part of the Prisoner Cohort Study* 1,396 male prisoners in England and Wales were interviewed between six and twelve months before their release. All prisoners included were serving determinate sentences of two or more years for a sexual or violent offence.

A Queen Mary University of London release reports that the prisoners interviewed were assessed for personality disorders, symptoms of schizophrenia, depression and drug and alcohol dependence, while the Hare Psychopathy Check List (Revised) (PCL-R) was used to measure psychopathic personality. The outcome was whether or not prisoners had at least one conviction for a violent offence within three years of release recorded in the U.K. Police National Computer. Three different re-offending risk assessment tools were used to compare their performance**.

The results showed:

• All three assessment tools performed moderately to well when no mental health disorder was present.
• Results were no better than moderate for those diagnosed with schizophrenia (average accuracy over the three assessment 59.5 per cent) and depression (average accuracy 60.8 per cent).
• There was further reduction for those with substance abuse disorders (average accuracy 55.5 per cent for those with drug dependence and 59.5 per cent for individuals with an alcohol disorder).
• For prisoners with antisocial personality disorders the predictive value of the tests ranged from poor to no more than chance (average 53.2 per cent predictive accuracy).
• For the 70 prisoners who rated high on the measure of psychopathic personality, none of the tests were statistically better than chance (average accuracy 46.7 per cent).