Predicting violence using structured professional judgment in patients with different mental and behavioral disorders.

We examined whether a leading instrument for the prediction of future violence in those with a mental disorder. The Historical, Clinical, Risk Management-20 (HCR-20) was equally effective across a wide range of mental health diagnoses. Records at the time of discharge from secure psychiatric services were used to score the HCR-20 risk assessment scheme. Patients were stratified according to whether they had received a particular mental health diagnosis. Reconvictions within 2 years of discharge were obtained from official sources and classified as to whether the offence was violent or not. Those with a diagnosis of either personality disorder or substance abuse were most likely to be reconvicted, whilst those with either a diagnosis of schizophrenia or mental retardation were the least likely. The HCR-20 was a statistically significant predictor of future violence in all groups; however, it returned only weak effects for the personality disordered group, but strong effects for those in the schizophrenia or mental retardation group. The HCR-20 risk assessment scheme is effective across a wide range of diagnoses. Nevertheless, the prediction of future events appears more difficult in those disorders characterized by impulsive behaviors and further research efforts are needed to understand how such prediction can be improved.