Forensic mental health intellectual and developmental disability service: an analysis of referral patterns and comparison with community mental health intellectual disability (MHID) services in Ireland

Purpose The purpose of this study is to analyse the characteristics of all the referrals to the forensic MHIDD service over the past five years and to compare these characteristics to the cohort of service users attending the three general MHID services based in Dublin which are Service 1, Service 2 and Service 3. Design/methodology/approach This is a cross-sectional study of adults attending the three generic MHID services and the national forensic MHIDD service. The medical files of service users attending the MHID services were reviewed, and data such as age, gender, level of intellectual disability and psychiatric diagnoses were extracted and compiled into a database. The forensic MHIDD service has since its inception maintained a database of all referrals received and reviewed. The characteristics data needed were extracted from the forensic MHIDD database. All these data were then analysed using the Statistical Package for Social Sciences (SPSS). Findings The majority of the three MHID service users were in the moderate to profound range of intellectual disability, while the majority of the cases assessed by forensic MHIDD had normal IQ, borderline IQ and mild intellectual disability with 66.1%. The prevalence of neurodevelopmental disorder, schizophrenia and emotionally unstable personality disorder in the forensic MHIDD is comparable to the three MHID services. The prevalence of depression, bipolar affective disorder (BPAD), anxiety disorder and obsessive-compulsive disorder (OCD) is higher in the three MHID services than in the forensic MHIDD service. Originality/value The FHMIDD received referrals at a greater level of overall ability, with two-thirds of the service users having mild intellectual disability to normal IQ. The prevalence of neurodevelopmental disorder such as ASD and schizophrenia is comparable between the forensic MHIDD and the three MHID services. There is a higher prevalence of depression, BPAD, anxiety disorder and OCD in the three MHID services as compared to the forensic MHIDD service.