NADD Bulletin Volume XI Number 3 Article 1

Complete listing

Supporting People at Risk of Unlawful Behavior

Marc Goldman, M.S.

Although most individuals with developmental disabilities are law-abiding citizens, social concern and clinical activity reflecting the relationship between crime and developmental disabilities can be traced back a century and remains of considerable, and perhaps growing, significance today (Gardner, Graeber, & Machkovitz, 1998; Lindsay, 2002). There has been an increase in research on forensic issues and services for people with developmental disabilities during the last ten years (Lindsay, 2002).

Vulnerability to the Criminal Justice System

Upon his or her first interaction with police, a person with intellectual disability is likely to speak and behave in ways that increase possibility of arrest and punishment (Perske, 1991). Fear, or lack of comprehension, might result in behaviors interpreted by the criminal justice system as cavalier, arrogant, or defiant. Inability to comprehend the serious nature of their situation, lack of support, and lack of adequate counsel results in the individual being vulnerable to more assertive booking, interrogation, incarceration, and retention by the criminal justice system than is experienced by nondisabled peers (Lindsay, 2002). It is doubtful that many individuals with developmental disabilities, unless they have had specific training, understand that police are entitled to employ devious methods in order to obtain confessions, or that everyone has a constitutional right to an attorney when charged with a crime. Ericson and Perlman (2001) reported that individuals with developmental disabilities demonstrated poor comprehension of a variety of legal terms that were believed to "undoubtedly arise in typical legal situations." For example, many of the participants in this study (45%) did not understand the concept of "guilty" and some reversed the meaning of "guilty" and "innocent."

Prevalence of Criminal Behavior

Although research indicates that people having developmental disabilities can be identified within the criminal justice system, prevalence estimates of the proportion of inmates with mental retardation or other developmental disabilities have varied widely, and often do not include those on probation or parole, or diverted to other programs (Goldman, 1997; Hawk, Rosenfeld, & Warren, 1993; Mason & Murphy, 2002). ). State correctional agency data that have been reported suggest prevalence rates among U.S. states within inmate populations ranging from 0.5% to 19.1% (Noble & Conley, 1992).

Although estimates of the percentage of persons having developmental delay within the population of sexual offenders are wide in range, they do suggest a higher than expected rate. Hawk, Rosenfeld, and Warren (1993) argued that estimates of prevalence of sex offenders having developmental disabilities might significantly underestimate true prevalence, because they are based on data obtained from prisons, and do not include those charged but diverted to alternative settings. They investigated the specific charges against individuals who underwent forensic assessment in Virginia over a six-year period and found that the rate of sex offense charges was almost twice as high among individuals with developmental disabilities than among other defendants. Day (1997) reported that people with developmental disabilities are over-represented in all studies of sex offences. Griffiths (2002) reported percentages of persons with developmental disabilities among the population of sexual offenders ranging from 3-4% to 15-33%.

Risk Assessment

Risk assessment has been described as the evaluation of the likelihood that a person will commit a new offense and the conditions that influence possible reoffense. There are numerous points within the criminal justice system where the assessment of risk of future violent behavior is germane (Heilbrun & Griffin, 1998).

In addition to completion of risk assessments in order to inform the criminal justice system of recidivism risk, many providers of services for people having developmental disabilities seek such information for individuals believed to be dangerous despite limited or nil court involvement. Turner (2000) reported that service providers are under increasing pressure to measure and control risks despite conceptual and measurement problems pertaining to the concept of dangerousness. Such non-court related risk assessments are completed to determine appropriate safety, treatment or habilitation, and staff support needs. Although risk assessment instruments are becoming increasingly sophisticated and combine various sources of information, they are based on studies of populations that may present risks or risk factors that are directly generalizable to individuals with intellectual disabilities. Currently, there is a lack of empirical evidence supporting the validity of forensic assessment tools when used in evaluation of people having developmental disabilities (Johnston, 2002; Turner 2000). Griffiths (2002) has cautioned that some risk assessment instruments are being used with people with developmental disabilities despite lack of evidence that they are valid for the population.

Modern day risk assessments are based on actuarial models and focus on static or historical variables such as criminal history, childhood adjustment, and paraphilia. Those treating or supervising individuals at risk of criminal behavior must also consider dynamic or variable risk factors. Dynamic factors include those that might change rapidly, such as access to victims, and might result in destabilization such as mental status and mood, drug use, and social or environmental influences (e.g., changes in level of available supervision, association with other people who themselves present risk of criminal offence). Dynamic risk factors can be used in the community to assist in determining when the level of supervision should be changed to lower an individual's risk (Quinsey 2004).

Determination of the likelihood that an individual will engage in aberrant sexuality in the future and understanding the circumstances under which such behavior would most likely occur makes up the process of risk assessment of sexual offense. Although Doren (cited in Mussack & Carich, 2001) developed a list of thirty risk assessment instruments and Prentsky and Edmunds (1977) compiled over ninety instruments that are used by clinicians who work with sex offenders, there is no instrument that is adequately validated for assessment purposes with people with developmental disabilities.

Along with determining risk, a comprehensive assessment provides information that guides treatment strategies (Mikkelsen 2004). Given the lack of validated approaches to assessment of offenders and non-adjudicated people having developmental disabilities who are suspected of dangerous behavior, or known to have engaged in such behavior, care should be taken to gather as much information as possible from the individual, records, and collaterals, prior to estimating risk and developing treatment and intervention recommendations or plans. Assessment should remain ongoing, not only to obtain additional static information, but to also consider changes in dynamic factors. Risk prediction, restrictions, and treatment interventions should be developed through a combination of assessment results, information concerning offenders without intellectual impairment, and information from the field of developmental disabilities. Relying solely on research concerning offenders without developmental disabilities may result in inaccurate predictions, inappropriate interventions, or lack of needed treatments. Relying on one or several static or dynamic factors may result in an underestimate or overestimate of risk and will limit the development of treatment interventions.

Evaluation of an individual with developmental disabilities at risk of criminal behavior should include comprehensive examination of individual, social, and system characteristics (Gardner, Graeber, & Machkovitz, 1998; Griffiths, 2002; McGee & Menolascino, 1992).  Investigators have described static and dynamic variables that should be considered in risk assessment of sex offenders having developmental disabilities (Seghorn & Ball, 2000; Ward & Bosek; 2002). These include sex offense and other criminal behavior history; willingness to discuss the offense and cooperate with the assessment; acceptance of responsibility, remorse, deviant sexual interests, victim typology, mental illness, substance abuse, willingness for treatment adaptive and emotional functioning; social skills, and sexual knowledge and attitudes.

Community Safety Planning

Regardless of involvement of the criminal justice system, or whether the offensive behavior was of a sexual or non-sexual type, those supporting an individual having developmental disabilities in the community who is at risk of criminal behavior should develop and implement a safety plan designed to minimize risk of re-offence. The safety plan should be based on risk assessment information and include indicators of when the individual is at higher risk due to dynamic stressors. The plan should include the following:

Control of social and environmental risk factors: Access to potential victims must be restricted. This might include restrictions of housing location, visitors in the home, and community access, including intensity of supervision. Other influences established through assessment, such as use of pornography or drug and alcohol use that influence offending behavior should be restricted.

Interventions designed to reduce dynamic internal factors: Therapeutic interventions addressing psychological variables should be ongoing and provided by qualified providers. These might include teaching and practice of specific skills often provided by developmental disability agencies such as anger management or social skills training. Other interventions may require involvement of specialized providers experienced in accommodated sex offence or felony specific treatment.

Emergency or crisis indicators: The network of support providers should be aware of dynamic factors or indicators that the individual is at increased risk of offending. A process of notification of such indicators to a responsible party or treatment coordinator should be established. A change in management and supervision level should be considered when increased risk is observed.

Emergency or crisis procedures: Specific responses to crisis indicators that are designed to protect the individual and community from re-offence should be implemented when crisis indicators are recognized. Responses might include increased supervision or restrictions, additional treatment interventions, and notification to probation or parole officers depending upon the specifics of court orders or correctional history.

Established consequences of aberrant behaviors or offending behaviors: The individual, serving agencies, and professionals should understand pre-established responses to offending behavior and provisions must be established to assure that agencies and professionals can immediately implement such responses to offending behavior. Minimizing criminal behavior or giving the individual a "second chance" merely makes such behavior more likely in the future (on an actuarial basis), placing potential victims at risk of harm and the offender at risk of increasingly restrictive community sanctions, incarceration, or re-incarceration.


The disability community has developed assessment processes that identify areas of individual need for services or supports, but for the most part has been reluctant to expand the process to include criminal behavior. Functional Analysis, a traditional tool used in the developmental disabilities field, could be modified to evaluate the offender with intellectual disability (Lambrick & Glaser, 2004).

Given the apparent general reluctance of the developmental disability field to consider many of these difficult issues and provide specialized services, providers of assessment and treatment services to offenders without developmental disabilities are often called upon to assess people with intellectual disabilities without the advantage of understanding their special needs. Developmental disabilities professionals who are willing to provide services often find little research based evidence to support the selection of assessment tools and their responsible interpretation.


Assessment of individuals having intellectual disabilities at risk of criminal behavior requires the careful application of knowledge from two scientific fields. Both fields report a lack of information concerning offenders with intellectual disabilities. Both fields advocate assessment of multiple influences on aberrant behavior. Both fields acknowledge the need for a clearer understanding of numerous variables. Those involved in the support of individuals with intellectual disabilities at risk of criminal behavior must cautiously apply information from both fields as they question, evaluate, and modify their approaches to assessment and planning.


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