In the Grey and Often Overlooked Areas: Mild to Borderline Intellectual Disability in Adult Repeat Offenders

In the Grey and Often Overlooked Areas: Mild to Borderline Intellectual Disability in Adult Repeat Offenders

Featured Article | International Journal of Forensic Mental Health | 2022, Vol. 21, No. 1, 54-67

Intellectual Disability among Violent Repeat Offenders and Its Relation with Psychopathology and Self-Sufficiency


Victoria B. M. Verhejen; Public Health Service Amsterdam, Amsterdam, The Netherlands
Menno W. Segeren; Public Health Service Amsterdam, Amsterdam, The Netherlands
Thijs Fassaert; Public Health Service Amsterdam, Amsterdam, The Netherlands
Christel Grimbergen; Public Health Service, Amsterdam, Amsterdam, The Netherlands


Despite the recognized importance of mild to borderline intellectual disability (MBID) among offender populations, there is insufficient understanding of its prevalence and associations with other social-psychiatric problems. Therefore this study investigated MBID prevalence and its relation with psychopathology and self-sufficiency problems (SSPs) in important life domains among young adult violent repeat offenders (N = 432) enrolled in a focused deterrence program in Amsterdam. Offenders participated voluntarily in a social psychiatric screening which included the Screener for Intellectual Disability and Learning Disorders (SCIL) to assess MBID, the Dutch version of the self-sufficiency matrix (SSM-D) to assess SSPs, and an assessment of the presence of psychiatric disorders according to DSM method- ology. Results showed an MBID prevalence of 51.1%. Nearly all offenders presented with at least one psychiatric disorder (95.0%) and SSPs in multiple life-domains. Among MBID offenders, symptoms of mood- and anxiety disorders, substance dependency and higher variety in SSPs were more frequently observed than among non MBID offenders. These results indicate the importance of adapting communication and treatment programs to increase their responsivity to MBID offenders. Self-sufficiency problems, that may reflect shortcomings in adaptive functioning specifically among MBID offenders, can be considered criminogenic needs and should be targeted accordingly to reduce recidivism.


Intellectual disability; violent crime; offenders; self-sufficiency; psychopathology

Summary of the Research

 “…An important but understudied psychiatric disorder in the context of offender rehabilitation and crime prevention is intellectual disability (ID)…the ‘in between’ group of people with average or below average IQ [are] at a higher risk of developing criminal behavior. This appears to apply most strongly to people with a mild to borderline intellectual disability (MBID). Moreover, the MBID part of the offender populations is known to present with many characteristic differences and problems in various life-domains…Internationally, the composite MBID definition includes people with either a mild intellectual disability (MID; 55 < IQ < 70) or with borderline intellectual functioning (BIF; 70 < IQ < 85 with accompanying problems in adaptive functioning in terms of conceptual, social, and practical skills)…” (p. 54-55).

“…knowledge of MBID in the field of criminal justice is not widespread and in need of further investigation…psychiatric comorbidity in relation to MBID in forensic settings is an important issue to take into account as well, as people with ID have been shown to be at high risk to develop psychiatric disorders…the current study aims at delivering a prevalence estimate of MBID among young adult violent repeat offenders on the basis of a screening instrument for MBID. A secondary aim is to determine differences in psychiatric comorbidity between offenders with and without MBID. Third, we aim to determine if MBID offenders present with more functioning problems in important life-domains…This can be considered as a proxy measure for adaptive functioning problems…Based on previous research, we expect a high prevalence of MBID in this group…[and] expect more indications of psychopathology and reduced self-sufficiency among MBID offenders, compared to non MBID offenders” (p. 56).

“We performed a cross-sectional study in which male young adult violent repeat offenders with and without MBID were compared with regard to psychopathology and self-sufficiency…MBID was assessed with the Screener for Intelligence and Learning Disabilities (SCIL; Kaal et al., 2015)…The prevalence of MBID in a group of young adult violent repeat offenders…was 51.1%. Social-psychiatric screenings revealed that a strikingly large part of the study population (95.0%) presented with symptoms of one or more psychiatric disorders…Symptoms of DSM-IV Axis I disorders, specifically mood- and anxiety disorders, were more frequent among MBID offenders. Offenders with MBID also…[exhibited] more serious and higher diversity of self-sufficiency problems in important life domains. These differences were most pronounced in the life-domains daytime activities, community participation, social network, mental health and daily life skills. As expected, MBID prevalence was considerably elevated compared to the general population…The results of the study are supported by the fact that MBID offenders were on average lower educated, more often had followed special education in childhood and less were currently enrolled in an education. Our findings highlight the importance of investigating the prevalence of MBID rather than ID in serious offender groups” (p. 56-62).

“The estimated prevalence of psychiatric disorders for the total study population was even higher than what is reported in literature for the prevalence of psychiatric disorders in other forensic populations…What is important, however, is that we found the prevalence of psychopathology to be even higher in offenders with MBID compared to those without MBID, most prominently regarding mood and anxiety disorders. This finding…is important to underline because common approaches and treatment programs in mental health care are not properly adjusted to this target group…One explanation for the elevated prevalence of psychopathology in general, and more specifically in people with MBID, could be trauma exposure…” (p. 62).

Translating Research into Practice

“…Today, there is sufficient evidence that certain approaches, such as focused deterrence programs and detention after care programs…can achieve moderate but positive reductions in recidivism in particular groups of offenders. These approaches typically adhere to dynamic risk factors in accordance with the ‘What Works Principles…’ and the Risk-Needs-Responsivity model. This model states that proportionally the best results are achieved with offenders with a high recidivism risk. The higher the risk, the more extensive the intervention should be (i.e. the risk principle). In addition, effective (criminal) interventions focus on criminogenic needs, namely the characteristics, risk factors and problems of the offender that are directly related to his/her offending behavior (i.e. the needs principle)…” (p. 62).

“…Criminogenic needs are dynamic risk factors, because they can be changed by means of interventions…Finally, according to the responsivity principle, treatments and interventions should be adapted according to, amongst others, the intellectual and social capabilities of the offender. Considering the fact that the group of people with ID is well represented here, but also very heterogenous…interventions should be adapted to the specific characteristics of people with this condition to be effective in reducing recidivism…Hereby, earlier recognition of ID during CJS proceedings allows better and earlier responses and adequate individualized treatment…Using validated instruments that can be administered easily and quickly, like the SCIL, can be useful for this purpose…” (p. 62).

Additional Resources/Programs

“Several explanations for the high prevalence of MBID among offenders have been offered. First, problems in executive functioning (specially working memory and attention tasks) are associated with antisocial behavior…As a lower level of intelligence is associated with problems in executive functions, these defective functions might be even more pronounced in people with ID and antisocial behavior…Second, ID is often accompanied by specific functional disorders, such as impulse control impairment, which is considered a risk factor for antisocial behavior and delinquency…Third, many criminogenic factors, such as a low socio-economic status, a social network with limited pro-social role models, lack of formal daytime activities…and a poor living environment are more common among people with an ID…Fourth, it is known that people with ID are sensitive or susceptible to peer pressure, resulting in that they are more easily persuaded to committing offenses by antisocial/criminal peers…” (p. 55).

“The presence of MBID is notoriously difficult to ascertain. Existing methods to indicate MBID have various disadvantages. MBID is often defined on the basis of a (total) IQ score, obtained with a validated intelligence test (e.g., WAIS-IV; Wechsler, 2012). IQ-tests are expensive and time-consuming, which may be problematic specifically among offender populations…a much neglected problem is that of a disharmonious intelligence profile which is established on the basis of significant differences in cognitive functioning between multiple subdomains of an IQ test (e.g., verbal and performal IQ)…A disharmonious intelligence profile precludes the computation of a total IQ score and, hence, its use to determine the presence of a MBID” (p. 55-56).

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