Individuals with Dangerous and Severe Personality Disorder (DSPD) are those who pose a significant risk of serious harm to others as a result of their severe personality disorder. Currently, potential DSPD prisoners are identified in the eight prisons in the high security estate of the United Kingdom, are screened, and asked if they are willing to come to the Whitemoor DSPD unit. The basis for treatment at the Whitemoor DSPD unit is Dialectical Behavior Therapy (DBT). This treatment goal is to improve personal and social functioning, to improve emotional regulation, to reduce the risk of harm to self and others, to reduce the person’s distress, and to improve a person’s amenability to treatment for sexual and violent offending. This study attempts to assess the feasibility of evaluating the Whitemoor Intervention pilot for those assessed as DSPD using a randomized controlled trial (RCT). A RCT equates persons in a treated group with persons in a control group on all possible variables that influence key outcomes. Research is needed to develop instruments that could measure change in the outcome measures, such as risk of committing serious violent or sexual crimes. It is recommended that a minimum sample size would need to be established in order to detect the likely effect of the treatment. This could be accomplished by using a statistical power analysis. In addition there are ethical issues to consider with the main issue centering on the denial of treatment to prisoners in the control group and the need for prisoners to voluntarily consent to participate in the research. The report concluded that a RCT could be feasible if: (1) potential subjects were assessed for DSPD in the eight feeder prisons; (2) several hundred DSPD prisoners were identified and were willing to participate in the RCT; (3) the case flow for DSPD assessment in Whitemoor was increased; (4) the length of the DBT-based treatment was shortened; and (5) DSPD prisoners deemed unsuitable for DBT were given other treatment. Efforts should continue to create the conditions making it feasible to evaluate the Whitemoor DSPD unit using RCT. References