This document provides an overview of risk assessment with intellectually disabled sex offenders. It discusses definitions of intellectual disability and risk assessment. It then reviews 6 studies that examined the predictive validity of various risk assessment instruments (e.g. VRAG, HCR-20, Static-99) for predicting recidivism in intellectually disabled sex offenders. The studies found that commonly used instruments can have sufficient or accurate predictive validity for this population, though more research is still needed, especially around predicting sexual recidivism after treatment.

1. Risk Assessment with Intellectually Disabled Sex Offenders: an Overview Association for the Treatment of Sexual Abusers 30 th Annual Research and Treatment Conference Milestones: Past, Present, Future 4 th November 2011 Jan Willem van den Berg

3. Intellectual Disability

4. Definition (1) Intellectual disability is characterized by significant limitations both in intellectual functioning and adaptive behavior as expressed in conceptual, social, and practical skills, which are apparent prior to the age of 18. American Association on Intellectual and Developmental Disabilities (AAIDD) 2010 IQ Levels Intellectually Disabled Highly talented Average Intelligence

5. Definition (2) I. Cognitive Abilities II . Adaptive Behavior III. Participation, Interaction and Social roles IV. Health V. Context Support Individual functioning AAIDD─model of intellectual disability (2010)

6. Support/risk model I. Cognitive abilities II . Adaptive Behavior III. Participation, Interaction and Social roles IV. Health V. Context Individual functioning AAIDD─model of intellectual disability (2010) VI. Risk level Support And Risk manage-ment

7. Risk Assessment

9. Risk Assessment (2) 5% 10% 20% 80% 80% 5% 5% 5% 5% 5% 10% 10% 10% 10% 20% 20% 20% 5% Former Days Nowadays

10. Probability The risk of sexual recidivism is neither 0% nor 100% Hanson & Thornton 2000 Static-99 category Sexual recidivism 5-15 year at risk Low 6-10% Moderate Low 10-17% Moderate High 28-37% High 39-52%

11. Predictive Validity How accurate do risk assessment instruments predict whether or not a sex offender will sexually reoffend? Douglas et al. 2007 AUC-value 0 Perfect negative prediction .50 Chance level (dice) .70 Reasonably accurate predictive validity >.75 Accurate predictive validity 1 Perfect positive prediction

12. Risk Assessment and Intellectual Disability

14. ‘ The proof of the pudding is in the eating’

15. Research on Predictive Validity

16. Method A review is done (Van den Berg & De Vogel 2011): On studies published between 1980 and 2011 on the predictive validity of risk assessment instruments used for assessing sex offenders with an intellectual disability. Results: Six articles were found that dealt with forensic risk assessment of intellectually disabled offenders which presented AUC-values.

17. Quinsey, Book, & Skilling (2004) Instrument: VRAG Participants: 58 sex offenders with an intellectual disability Follow-up period: 16 months after treatment Outcome measure: (sexually) violent incidents reported by staff Results: AUC .69

18. Gray, Fitzgerald, Taylor, MacCulloch, & Snowden (2007) Instrument: VRAG, HCR-20, PCL:SV Participants: 1141 forensic patients (145 with IQ<70) Follow-up period: 2 – 5 years Outcome measure: Conviction for violent and general offence Results: Predictive validity for violent recidivism for all instruments between AUC .73 - .81. No significant difference in predictive validity between the instruments.

19. Lindsay, Hogue, Taylor, Steptoe, Mooney, O’Brien, Johnston, & Smith (2008) Instruments: HCR-20, Static-99, Risk Matrix 2000 Participants: 212 Intellectually disabled offenders (IQ 65 – 67) Follow-up period: 12 month treatment Outcome measure: Incidents reported by staff Results: Predictive validity VRAG and HCR-20 for violent behavior AUC .71 and .72 Predictive validity Static-99 for sexually inappropriate behavior AUC .71 Predictive validity Risk Matrix 2000 for sexual and violent behavior AUC .62 and .61

20. Wilcox, Beech, Markall, & Blacker (2009) Instruments: Static-99, Risk Matrix 2000, RRASOR Participants: 27 intellectually disabled sex offenders (IQ<80) Follow-up period: 76 months Outcome measure: Conviction for sex offence Results: Predictive validity for all instruments between AUC .42 - .64

21. Morrissey, Hogue, Mooney, Allen, Johnston, Hollin, Lindsay, & Taylor (2007) Instruments: PCL-R, HCR-20 Participants: 60 intellectually disabled forensic patients (IQ 43-76) Follow-up period: 12 months treatment Outcome measure: Verbal / physical aggression reported by staff Results: Predictive validity for PCL-R on verbal / physical aggression AUC .49 and .54 Predictive validity of HCR-20 on verbal aggression and physical aggression AUC .77 and .68

22. Verbrugge, & Goodman-Delahunty (2011) Instruments: VRAG, HCR-20, HCR-20 (scored with ID supplement) * Participants: 59 community-based intellectually disabled offenders IQ <80) with a history of violent offences Follow-up period: 2 – 8.5 years after index offence Outcome measure: Any charge or conviction Results: The predictive validity for VRAG, HCR-20 and HCR-20 supplement was respectively for violent recidivisme AUC .79, .80, .80 and for general recidivism .92, .94, .97. Use of the ID supplement offered no statistically significant better results. * Boer et al. 2010

24. Conclusions

26. References Gray, N.S., Fitzgerald, S., Taylor, J., MacCullloch, M.J., & Snowden, R.J. (2007). Predicting future reconviction in offenders with intellectual disabilities: The predictive efficacy of VRAG, PCL:SV and the HCR-20. Psychological Assessment, 19, 474-479. Lindsay, W.L., Hogue, T.E., Taylor, J.L., Steptoe, L., Mooney, P., O’Brien, G., Johnston, S., & Smith, A.H.W. (2008). Risk assessment in offenders with intellectual disability. A comparison across three levels of security. International Journal of Offender Therapy and Comparative Criminology, 52, 90-111. Morrissey, C., Hogue, T., Mooney, P., Allen, C., Johnston, S., Hollin, C., Lindsay, W.R., & Taylor, J.L. (2007). Predictive validity of the PCL-R in offenders with intellectual disability in a high secure hospital setting: Institutional aggression. The Journal of Forensic Psychiatry & Psychology, 18, 1-15.

27. References (2) Quinsey, V.L., Book, A., & Skilling, T.A. (2004). A follow-up of deinstitutionalized men with intellectual disabilities and histories of antisocial behavior. Journal of Applied Research in Intellectual Disabilities, 17, 243-253. Verbrugge, H.M., & Goodman-Delahunty, J. (2011). Risk Assessment in Intellectually Disabled Offenders: Validation of the Suggested ID Supplement to the HCR-20. International Journal of Forensic Mental Health, 10, 83-91. Wilcox, D., Beech, A., Markall, H.F., & Blacker, J. (2009). Actuarial risk assessment and recidivism in a sample of UK intellectually disabled sexual offenders. Journal of Sexual Aggression, 15, 97-106 .

28. Contact Information Jan Willem van den Berg Van der Hoeven Stichting Postbus 174, 3500 AD Utrecht The Netherlands Telefone: +31 (0)30-2758275 E-mail: jwvandenberg@hoevenkliniek.nl www.linkedin.com/in/janwillemvandenberg