Susan Johnston

Risk Assessment in Offenders With Intellectual Disability: A Comparison Across Three Levels of Security

In mainstream offender samples, several risk assessments have been evaluated for predictive validity. This study extends this work to male offenders with intellectual disabilities. Participants from high-, medium-, and low-security settings, as well as community settings, were compared on a range of risk assessments. The Violence Risk Appraisal Guide, HCR-20—Historical Scale, the Risk Matrix 2000-C (combined risk), and the Emotional Problems Scales—Internalising discriminated between groups, with participants from high security having higher scores than those in medium security, who had higher scores than those in the community. The Violence Risk Appraisal Guide, all HCR-20 scales, the Short Dynamic Risk Scale, and the Emotional Problems Scales (Internalising and Externalising) showed significant areas under the curve for the prediction of violence. The Static-99 showed a significant area under the curve for the prediction of sexual incidents. The discussion reviews the value of these various scales to intellectual disability services.

Two studies on the prevalence and validity of personality disorder in three forensic intellectual disability samples

Abstract There is an extensive research literature on the association between personality disorder, antisocial personality disorder, and risk of future violent and sexual offences. Several studies have found an elevated prevalence of personality disorder diagnoses amongst those individuals with severe mental illness and criminal populations. While there has been some work on the prevalence of personality disorder among intellectual disability populations, it has been criticised as being unreliable and inconsistent. The present authors have taken account of these criticisms and recommendations in this comparison of 164 offenders with intellectual disability across three settings – community, medium/low secure, and high secure. In Study 1, DSM-IV diagnoses were made on the basis of four information sources: file review, interview with clinician, observations by care staff, and the Structured Assessment of Personality Interview. Across the samples, total prevalence of PD was 39.3%. The most common diagnosis was antisocial personality disorder. There was a higher rate of diagnosis in the high security setting, with no significant differences between the other two settings. There was no diagnosis of dependent PD, indicating that assessors were not overly influenced by the developmental disability itself. In Study 2 it was found that increase in severity of PD (as indicated by PCL-R scores and/or the number of PD diagnoses) showed a strong lawful relationship with instruments predicting future violence (VRAG, RM 2000/V) and a weaker relationship with instruments predicting future sexual offences (Static-99, RM 2000/S). The results indicate the utility of PD classification in this client group and that a number of individuals with PD classification are being managed successfully in community settings. These findings have considerable implications for staffing, both in terms of which individuals can be treated by these services and staff training.

Pathways Into Services for Offenders with Intellectual Disabilities Childhood Experiences, Diagnostic Information, and Offense Variables

The patterns and pathways into intellectual disability (ID) offender services were studied through case file review for 477 participants referred in one calendar year to community generic, community forensic, and low, medium, and maximum secure services. Data were gathered on referral source, demographic information, index behavior, prior problem behaviors, diagnostic information, and abuse or deprivation. Community referrers tended to refer to community services and secure service referrers to secure services. Physical and verbal violence were the most frequent index behaviors, whereas contact sexual offenses were more prominent in maximum security. Age at first incident varied with security, with the youngest in maximum secure services. Attention-deficit/hyperactivity disorder or conduct disorder was the most frequently recorded diagnosis, and severe deprivation was the most frequent adverse developmental experience. Fire starting, theft, and road traffic offenses did not feature prominently. Generic community services accepted a number of referrals with forensic-type behavior and had higher proportions of both women and people with moderate or severe ID.

Applicability, Reliability and Validity of the Psychopathy Checklist-Revised in Offenders with Intellectual Disabilities: Some Initial Findings

As a part of a larger study, the Psychopathy Checklist-Revised (PCL-R) was used to assess psychopathy in 203 individuals from three UK National Health Service settings for offenders with intellectual disabilities (ID): a high security hospital, a medium and low security hospital and a community based service. The PCL-R was rated from file review combined with a clinician interview. Internal consistency and inter-rater reliability were acceptable, and broadly comparable to that reported for other offender populations. The instrument was also associated in largely expected ways with level of security, and with measures of antisocial personality disorder, risk, and current behavioural functioning, providing some preliminary indications of convergent validity. However, further empirical investigation is required before the PCL-R can be used with confidence to make clinical and risk-based decisions in this population.

Community services and people with intellectual disabilities who engage in anti-social or offending behaviour: referral rates, characteristics, and care pathways

Provision of health and social support to people who engage in anti-social or offending behaviour and have intellectual disabilities (ID) remains a challenge to services. Numerous population studies have produced contradictory findings with reviews calling for the development of more fruitful approaches and recommending investigation of the care pathways operating within ID services. This study reports on the pathways through services encountered by adults with offending or anti-social behaviour referred to 15 UK community ID services in 2002. Pathways through services were tracked for 24 months post referral. Referral rates, demographic characteristics, and associations with anti-social or offending behaviour were statistically analysed for 237 cases. Most referrals originated from the local community (66%); a high proportion were female (40.5%). Community services appeared encapsulated, serving adults with offending behaviour over the long term, but predominantly (74%) those already known to local ID services. Implications for services and future research strategies are considered.

The relationship between assessed risk and service security level for offenders with intellectual disability

Following social policies of deinstitutionalisation, few offenders with intellectual disability (ID) are diverted into local hospitals and they are now referred to a range of community and secure services. Of 197 participants, the Violence Risk Appraisal Guide was completed on 181 and the Static-99 on 83. Assessed risk was then related to six levels of service: community generic, specialist community forensic ID, learning disability in patient, low secure, medium secure and high secure. On both assessments, those in high secure had a significantly greater average assessed risk than in the community. Correlations between assessed risk and level of service showed low to medium effect sizes. Despite an orderly relationship between assessed risk and level of security, the effect sizes are not large suggesting that factors may intervene to place some individuals of a high risk in community settings and others of a low risk in secure settings.

Internal consistency and factor structure of personality disorders in a forensic intellectual disability sample

Abstract Background The publication of the DSM‐III (American Psychiatric Association (APA), 1980) prompted a significant increase in interest and research on personality disorder (PD), and the concept has subsequently been incorporated into mental health legislation in the developed world. Despite this, such research on people with intellectual disability (ID) has been sporadic, with widely varying results. The present study addresses a number of criticisms directed at previous research. Method DSM‐IV (APA, 2000) diagnoses of PD were made on 164 participants with ID on the basis of four independent sources of classification. Results Reliability data for each PD was acceptable and alpha was .74 or above, with the exception of schizotypal PD (.63). Exploratory and confirmatory factor analyses were conducted, with the former revealing a 4‐factor solution accounting for 58.9% of the variance, and a 2‐factor solution accounting for 37.2% of the variance emerging for the latter. The factors were orthogonal, and we called the first factor “avoidant/rumination/inhibited” and the second factor “acting out”. Discussion We review these findings in relation to previous research on PD and alternative frameworks for the understanding of personality. We hypothesise consistencies between these findings and previous work on personality and ID. A number of drawbacks to the research are discussed, including a caution on the pejorative nature of a diagnosis of PD in an already devalued population.

Referrals into services for offenders with intellectual disabilities: variables predicting community or secure provision.

BACKGROUND There is a need for research to promote an understanding among service developers on why people with intellectual disabilities (ID) are referred to offender services in order for them to receive appropriate assessment and treatment. Previous studies investigating referrals into forensic ID services have concentrated on referral sources and administrative variables such as legal status. AIMS To construct a predictive model for choice of service referral based on a comprehensive range of information about the clientele. METHOD We conducted a case record study of 336 people referred to community services and 141 to secure provision. We gathered information on referral source, demographics, diagnosis, index behaviour, prior problem behaviours and history of abuse. RESULTS Comparisons revealed 19 candidate variables which were then entered into multivariate logistic regression. The resulting model retained six variables: community living at time of referral, physical aggression, being charged, referral from tertiary health care, diverse problem behaviour and IQ < 50, which correctly predicted the referral pathway for 85.7% of cases. CONCLUSIONS An index act of physical aggression and a history of diversity of problem behaviours as predictors against the likelihood of community service referral suggest that professionals have similar concerns about people with ID as they do about their more average offending peers; however, the more severe levels of ID mitigated in favour of community referral, regardless. Offenders with ID tend to be referred within levels of service rather than between them, for example, form tertiary services into generic community services.

Pathways through services for offenders with intellectual disability: a one- and two-year follow-up study.

The pathways through services for offenders with intellectual disability were reviewed. Participants were 197 offenders with intellectual disability accepted into three types of community and three types of secure forensic intellectual disability services. They were first compared with 280 participants referred but not accepted into services and were then followed-up for 2 years to review pathways through services. Those accepted into services had a higher charge rate than did those who were referred (46% and 25%, respectively). The greatest diversity in pathway was seen in participants in community forensic intellectual disability and inpatient services. Individuals in secure settings showed the least diversity over time, and, similarly, a relatively high percentage of those accepted into generic community services remained in these services.