Admission to one of the Dangerous and Severe Personality Disordered (DSPD) services in England and Wales is heavily determined by risk status and monitoring of changes in risk over time is a core procedure. However, the extent to which DSPD services are effective in terms of reducing risk is one of the most important questions yet to be answered. This paper seeks to examine whether risk, as measured by the Historical-Clinical-Risk-20 (HCR-20) (Webster et al. 1997), posed by patients admitted to a high-secure psychiatric DSPD unit reduces according to length of time in the unit.

Admission and discharge/current treatment status HCR-20 measures were collected for 58 concurrent DSPD admissions for period 25th March 2004 to 22nd July 2009.

Overall longer ‘treatment’ times were associated with lower scores on the dynamic risk scales of the HCR-20 for a group of patients admitted to the high secure DSPD facility. Specifically, Clinical and Risk scores both reduced by .05 points (monthly). Historical risk did not change over time.

These changes are promising, since positive changes in a high-risk group of mentally disordered offenders on such factors as insight and impulsivity are known to be hard to accomplish. The results provide support for the proposition that the C and R scales of the HCR-20 are dynamic. Attention to whether risk reduction translates to lower institutional infractions and future recidivism is recommended.