Post-traumatic stress disorder and experiences involving violence or sexual abuse in a clinical sample of autistic adults with intellectual disabilities: Prevalence and clinical correlates
Authors: Kildahl Arvid Nikolai , Helverschou Sissel Berge 
Published: August 2023

Autistic people appear to be at increased risk of post-traumatic stress disorder, and experiences involving violence or sexual abuse appear to be common in this population. However, knowledge concerning trauma in autistic people with co-occurring intellectual disabilities is limited. In this cross-sectional study, we explored the prevalence of post-traumatic stress disorder, as well as the prevalence and clinical correlates of reported experiences of violence and sexual abuse, in a clinical sample of 88 autistic adults with intellectual disabilities referred for mental health assessment. Only three participants (3.4%) were diagnosed with post-traumatic stress disorder, even if experiences involving violence (34.1%) or sexual abuse (17.0%) were common. Anxiety and affective disorders were common diagnoses among participants with these experiences. Controlling for autism characteristics, level of intellectual disability and communication skills, experiences of violence/sexual abuse were found to be associated with a measure of ‘challenging’ behaviours (Aberrant Behaviour Checklist). These results indicate that potentially traumatic experiences are common in autistic adults with intellectual disabilities referred for mental health assessment and that post-traumatic stress disorder may be under-recognised. The findings highlight the importance of trauma screening and post-traumatic stress disorder assessment, as well as the importance of trauma-informed care, in this population. Lay abstract Post-traumatic stress disorder is a mental health disorder that may be triggered by the experience of events perceived as terrifying or overwhelming. Examples of such events include being the victim of violence or sexual abuse. Compared with other people, autistic people have increased risk of being exposed to violence or sexual abuse. In addition, autistic people may be more vulnerable to developing post-traumatic stress disorder following such exposure. However, knowledge is limited concerning the prevalence of experiences involving violence and sexual abuse, and post-traumatic stress disorder, in autistic people with co-occurring intellectual disabilities. Detection of these experiences, and identification of post-traumatic stress disorder, may be challenging in these individuals, and previous research indicates that post-traumatic stress disorder symptoms may be overlooked or misinterpreted. In this study, we examined prevalence of post-traumatic stress disorder, violence and sexual abuse in a clinical sample of 88 autistic adults with intellectual disabilities referred for mental health assessment. Only 3.4% were diagnosed with post-traumatic stress disorder, even if experiences involving violence (34.1%) or sexual abuse (17.0%) were common. Anxiety and affective disorders were common diagnoses among participants with these experiences. Controlling for autism characteristics, level of intellectual disability and communication skills, experiences of violence/sexual abuse were found to be associated with a measure of ‘challenging’ behaviours. These results indicate that potentially traumatic experiences are common in autistic adults with intellectual disabilities referred for mental health assessment, and that post-traumatic stress disorder may be under-recognised. The findings highlight the importance of trauma screening and post-traumatic stress disorder assessment, as well as the importance of trauma-informed care, in this population.