Researchers find tests meant to predict future violence by psychopaths is less accurate than chance

Predicting violence among psychopaths is no more than chance

(Medical Xpress)—A trio of British researchers has conducted a study that has revealed that tests given to jailed psychopaths to predict the likelihood of engaging in future violence, are less accurate than chance. In their paper published in the British Journal of Psychiatry, Jeremy Coid, Simone Ullrich and Constantinos Kallis describe how they interviewed and gave tests to inmates in British prisons and then followed up later to see if they engaged in violent activities after release—they found that tests given to predict such behavior in psychopaths were no better than 50 percent accurate.

In order to protect the public, trained psychology professionals are often asked to assess the likelihood of an incarcerated person engaging in illegal activities when authorities are considering whether or not such a person should be released before their sentence is up. Unfortunately, giving tests and interpreting their results has not yet proved to be a reliable science. In this new study in Britain, the researchers conducted interviews and gave psychological tests to 1,396 inmates imprisoned in England and Wales, six months to a year before their release—afterwards re-offense records were studied to compare with future activities.

The tests given to the inmates were meant to discover if they had mental impairments, and if so, which ones—that allowed for testing of re-offending rates to see how well the tests were able to predict future tendencies. The for assessing whether a person is a psychopath (one who is amoral) is considered to be highly reliable and is also used to predict whether a person will engage in future violent activities.

In analyzing the results, the researchers found that the tests did reasonably well in predicting behavior in people with no discernible mental illness—they proved to be approximately 75 percent right in predicting whether they would be jailed again for . The tests were less accurate for those with mental ailments such as schizophrenia, with a success rate of just 60 percent. Predicting whether a person diagnosed as a would re-offend, sadly, was no better than 50 percent, which, the researchers point out, is no better than flipping a coin. For this reason, they suggest that courts stop using such tests when considering early release of such prisoners.

More information: Predicting future violence among individuals with psychopathy, Published online ahead of print September 26, 2013, DOI: 10.1192/bjp.bp.112.118471

Structured risk assessment aims to help clinicians classify offenders according to likelihood of future violent and criminal behaviour. We investigated how confident clinicians can be using three commonly used instruments (HCR-20, VRAG, OGRS-II) in individuals with different diagnoses. Moderate to good predictive accuracy for future violence was achieved for released prisoners with no mental disorder, low to moderate for clinical syndromes and personality disorder, but accuracy was no better than chance for individuals with psychopathy. Comprehensive diagnostic assessment should precede an assessment of risk. Risk assessment instruments cannot be relied upon when managing public risk from individuals with psychopathy.

Press release

Journal information: British Journal of Psychiatry

© 2013 Medical Xpress

Citation: Researchers find tests meant to predict future violence by psychopaths is less accurate than chance (2013, October 2) retrieved 2 December 2023 from
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