Autistic Traits in Patients within Secure Forensic Mental Health Settings

Background: Previous research has reported a higher prevalence of Autism Spectrum Disorder (ASD) in forensic settings compared with the general population. There has been a gradual shift to a broader conceptualisation of the autism phenotype incorporating both categorical and dimensional approaches. However, there is limited research into autistic traits within forensic mental health settings, and few studies have evaluated profiles of traits within this sample.

 Objectives:  The aim of the study was to examine the prevalence of autistic traits in a forensic population by systematically screening for ASD in medium and high secure forensic mental health services.

Methods:  Clinicians responsible for wards within Broadmoor Hospital and River House at the Royal Bethlem Hospital identified eligible cases according to inclusion and exclusion criteria. The sample consisted of male inpatients with mental health problems (MHP) such as paranoid schizophrenia and/or Personality Disorder (PD) such as anti-social or borderline. 131 individuals were screened using the self-report Autism Quotient (AQ) comprising 50 items, including 10 questions assessing five different subscales of functioning (social skills, communication, switching attention, attention to detail, imagination) which were summed to give a total AQ score, with a maximum possible score of 50.  Higher AQ scores represent a higher number of ASD traits. The recommended cut-off scores for further evaluation are 32 in the general population and 26 for clinical populations.

Results:  A previous study used the AQ to screen males in the general population and this data was used as a comparison sample.  Examining the distribution of AQ scores revealed that 11 (8%) of the total sample had scores of 32 or above, and 31 (24%) had scores of 26 or above. One sample t-test analysis indicated that the sample AQ scores were significantly greater than the general male population score of 17.8 (M=20.74, SD=6.88, t(130)=4.90, p<.001, d=.4). Significant differences were also found between the forensic sample and the general population for all five subscales of the AQ. Forensic patients showed significantly higher AQ scores compared with the general male population on all areas of functioning except for attention to detail (all p≤.05).

Conclusions:  The prevalence of autistic traits in the current sample of forensic patients is greater than that reported for the general male population. The findings also provide a provisional AQ profile for forensic populations, as results revealed poorer social and communication skills, poorer imagination and attention switching, but less focused attention in the forensic sample compared with the general male population.