Current Treatment Modalities May Not Fully Address the Heterogeneity of Psychopathology in Dual Diagnosis Forensic Inpatient Populations

Audrey Vicenzutto, Service de Psychopathologie Legale, Universite de Mons, Mons, Belgium
Xavier Saloppe, Centre de Recherche en Defense Sociale, CRDS, Tournai, Belgium; Laboratoire de sciences Cognitives et affectives (SCALab), CRNS, UMR 9193, Universite de Lille, Villeneuve-d’Ascq, France; Service de psychiatrie, Hopital de Saint-Amand-les-Eaux, Saint-Amand-les-Eaux, France
Claire Ducro, Centre de Recherche en Defense Sociale, CRDS, Tournai, Belgium; Laboratoire de sciences Cognitives et affectives (SCALab), CRNS, UMR 9193, Universite de Lille, Villeneuve-d’Ascq, France
Vanessa Milazzo, Hopital Psychiatrique Securise, Centre Regional Psychiatrique “Les Marronniers”, Tournai, Belgium
Murielle Lindekens
Thierry H. Pham, Service de Psychopathologie Legale, Universite de Mons, Mons, Belgium; Centre de Recherche en Defense Sociale, CRDS, Tournai, Belgium; Centre de Recherche, Institut Philippe-Pinel, Montreal, Canada

While the prevalence of mental disorders in people with intellectual disabilities (ID) is well documented, there is less specific literature in the forensic domain. This study sought to clarify the psychiatric and criminological characteristics among Belgian French-speaker forensic inpatients with low IQ and mental health illnesses. To this end, we compared a low IQ group with mental health illnesses (n.69), low IQ group (n.56), and control group (n.165). Compared with controls, proportionally more inpatients low IQ with Mental Health Illnesses presented a psychiatric illness, particularly a mood disorder, and proportionally fewer presented a cluster C personality disorder. The findings highlight the specificity and heterogeneity of the psychiatric profile of this subgroup of patients. We also demonstrated that forensic patients with ID are not a homogeneous group. This emphasizes the importance of considering in the management of forensic ID patients the specific needs with regard to their psychopathological profile.

Low IQ, psychiatric comorbidities, dual diagnosis, forensic facilities, intellectual disability

“While there is no consensus on the definition of Intellectual Disability (ID), the comparison of proposed definitions in North America and Europe agrees that three diagnostic criteria are required: limitations in intellectual functioning, limitations in adaptive behavior, and the occurrence of these difficulties before the age of 18 years…Research indicates that people with intellectual disability are over-represented among prison populations. According to these authors, it is possible that there is a difference in rates of remand detention for similar offenses between offenders with and without ID…Where forensic populations are concerned, few studies have sought to gauge the prevalence of ID in secure psychiatric hospitals…numerous studies have evidenced that these persons are particularly vulnerable within the criminal justice system, particularly because they are at higher risk for physical, sexual, and emotional victimization…In the field of ID, the term dual diagnosis (DD), is used to refer to persons with co-occurring diagnoses, namely, ID and a psychiatric illness…” (p.272-273).

“Researchers have stated that identifying the characteristics specific to persons with DD was key to developing interventions tailored to their needs. It has also been shown that psychiatric disorders, particularly schizophrenia and mood disorders, were associated with prolonged lengths of stay for persons with ID in general psychiatric settings…there is no study on ID and DD among French-speaking forensic inpatient[s] in Belgium. And based on the observation that ID assessment[s], according to the international classifications, are not systematized in clinical practice in this environment, this preliminary study aims to establish the prevalence rate of low IQ with Mental Health Illnesses and, second, to characterize their diagnostic (DSM-IV Axes I and II) and social profile” (p.274-275).

“Regarding the study’s first objective concerning the prevalence of patients with low IQ and Mental Health Illnesses in [a] secure psychiatric hospital, several results emerged worthy of note. First, 41.1% of the sample was composed of patients with an IQ below 70. This rate exceeds by far the numbers reported in the literature…Moreover, the prevalence we observed is far greater than available international figures…Regarding more specifically [the] low IQ MHI group, we observed a prevalence of 22.7% in the forensic population as a whole. Within the subgroup of forensic inpatients with Low IQ, the prevalence was 55.2%” (p.279).

“Regarding the study’s second objective, the results indicated that, all diagnostic categories considered, proportionally more persons from [the] low IQ MHI group presented [with] Axis I disorders compared with the Control group, particularly when it came to mood disorders…Alongside this specificity, a diagnostic heterogeneity emerged among Low IQ with Mental Health Illnesses patients, as reflected in the high prevalence of psychotic disorders, anxiety disorders and addictions in this group. However, the results revealed no significant inter-group differences on these three diagnostic categories…Where personality disorders are concerned, given the specificity of the forensic population, we expected both the Low I! MHI group and the Control group to present a high prevalence of Axis II disorders, especially those in cluster B. While we did observe a high prevalence of cluster A and B disorders in both groups at nearly equivalent levels, a significantly lower proportion of patients from Low IQ MHI group presented with a cluster C disorder” (p.280)

“…Existing adaptive behavior scales have not been validated in forensic settings. This is critical in that these scales are often of the self-report type. In the legal field, this creates difficulties, mainly related to evaluation issues…Future research should focus on the development of assessment tools in the aim of addressing the limitations mentioned above. A number of French-language scales already exist to assess adaptive behaviors, including the Quebec Scale of Adaptive Behavior. However, to our knowledge, this instrument has never been standardized for forensic purposes” (p.280).

“…While psychiatric disorders are common in the ID population, they are often poorly identified and their evaluation poses a genuine clinical challenge…the more attention is paid to DD, the more the need for adapted means of evaluation and tailored treatment will be recognized. Future research will have to develop tools for assessing psychiatric disorders in this subgroup, but also reflect upon adapting diagnostic criteria to its specificities and developing appropriate training programs for clinicians…we would do well to implement care programs adapted to the specificities of forensic patients with ID with and without a psychiatric comorbidity” (p.281).

“While it has been shown that people with ID often have psychosocial difficulties, out analysis of social profile evidenced proportionally more patients in the Low IQ MHI group and the Control group maintained a marital relation, compared with those in the Low IQ group. This raises the question of the different role of the family in the treatment of psychiatric illness versus the management of disabilities. Proportionally more patients in the Low IQ MHI group and in the Control group lived alone prior to admission whereas proportionally more patients in the Low IQ group lived with their family…In the future, it would be interesting to collect information on the life course of these persons” (p.280).

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