CNV predicts violent outcomes in patients released from special hospital

The ability of the Go/No Go contingent negative variation (CNV) to predict violent outcomes (violent re-offending and suicide) was investigated in a sample of 44 male Broadmoor patients previously (in 1983) categorised as high or low risk on the basis of their Go/No Go CNV. An earlier (December 1990) follow-up of the same sample had indicated that general criminal recidivism could be predicted by Go/No Go CNV (Howard & Lumsden, 1996). At 31 December 1994 a violent outcome had occurred in five of 21 high-risk patients and in one of 23 low-risk patients, yielding a predictive accuracy of 61.4% and a relative improvement over chance of 68%. High-risk patients incurred five times as many violent reconvictions as did low-risk patients. These results, whilst preliminary pending further follow-up, offer the promise that the tragic consequences of releasing high-risk mentally disordered offenders into the community might be prevented using a technique that is quick, cheap to administer and objective. Copyright © 1997 Whurr Publishers Ltd.