Background: Autistic adults experience high rates of traumatic events and posttraumatic stress disorder (PTSD) symptoms. However, less is known about how autistic adults experience (i.e., by directly experiencing, witnessing, and/or learning about) distinct types of traumatic events (e.g., social, nonsocial traumas). Little research has considered whether the four-factor structure of PTSD symptom domains (e.g., avoidance, intrusions, hypervigilance, negative mood/cognition) can be applied for autistic adults. Lastly, understanding how demographic factors (e.g., gender, race/ethnicity) relate to rates of traumatic events and symptoms among autistic adults is critical for understanding disparities relating to PTSD. Therefore, the current study aims to examine self-reported traumatic events and PTSD symptoms, and identify associations with demographic factors, among autistic adults.Methods: Participants included 276 autistic adults and a nationally representative sample of 361 nonautistic adults who completed online measures, including the Life Events Checklist for DSM-5, Posttraumatic Stress Disorder Checklist for DSM-5 (PCL-5), Autism-Spectrum Quotient-Short, and Patient Health Questionnaire-4. Analyses focused on evaluating group differences in traumatic events and symptoms and considered associations with demographic factors.Results: Autistic adults reported significantly higher rates of directly experiencing, witnessing, and learning about traumatic events than nonautistic adults, including more interpersonal events (e.g., physical assault, sexual assault) and fewer transportation accidents than nonautistic adults. Autistic adults also reported significantly higher levels of all PTSD symptom clusters than nonautistic adults. A confirmatory factor analysis and follow-up invariance analyses of the PCL-5 revealed that the four-factor Diagnostic and Statistical Manual of Mental Health Disorders, Fifth Edition (DSM-5) PTSD symptom subscale structure was equivalent across groups of autistic and nonautistic adults.Conclusion: Autistic adults experienced more traumatic events and PTSD symptoms overall, particularly more interpersonal traumas and hyperarousal and negative mood/cognition symptoms than nonautistic adults. Future research should examine outcomes of trauma exposure, identify protective factors, and examine efficacy of trauma-focused treatments for autistic individuals, in partnership with autistic adults. Community briefWhy is this an important issue?Autistic people experience more traumatic events and more symptoms of posttraumatic stress disorder (PTSD) than nonautistic people. Little is known about if PTSD symptoms can be measured similarly among autistic and nonautistic people. Studying trauma, PTSD, and how PTSD is measured is helpful for developing useful resources for autistic adults who experience trauma and PTSD.What was the purpose of this study?We wanted to compare how autistic adults and nonautistic adults experience traumatic events and symptoms of PTSD.What did the researchers do?Two-hundred seventy-six autistic adults and 361 nonautistic adults completed questionnaires through an online research platform. We used the Life Events Checklist for DSM-5 (LEC-5) to ask about traumatic events that adults may have experienced directly, witnessed, learned about, or experienced as part of one's job. We used the Posttraumatic Stress Disorder Checklist for DSM-5 (PCL-5) to measure PTSD symptoms, including intrusions (thinking about trauma when one does not want to), avoidance (staying away from thoughts or rteminders of trauma), hyperarousal (feeling restless, having difficulty concentrating), and negative thoughts and feelings (feeling depressed, thinking the world is unsafe). Participants also filled out the Autism-Spectrum Quotient-Short to measure autistic traits and the Patient Health Questionnaire-4 to measure depression and anxiety. The researchers looked to see if the PCL-5 questionnaire works differently when it is used by autistic and nonautistic adults.What were the results of the study?More traumatic events directly happened to autistic adults than nonautistic adults. Autistic adults also witnessed and learned about more traumatic events. Autistic adults experienced more interpersonal events than non-autistic adults (such as physical assault, sexual assault, other unwanted sexual experiences, and severe human suffering). They experienced fewer transportation accidents than non-autistic adults. Autistic adults had more PTSD symptoms than nonautistic adults, including more overall symptoms and more symptoms in each of the PTSD symptom categories (intrusions, avoidance, hyperarousal, negative thoughts and feelings). Also, the PCL-5 questionnaire measures PTSD symptoms similarly among autistic and nonautistic adults.What do these findings add to what was already known?Our results are consistent with other research showing more traumatic events for autistic than non-autistic people, and also show higher rates of seeing or learning about traumatic events. We also contribute new information about using the PCL-5 with autistic adults, which can help clinicians and other researchers.What are potential weaknesses in the study?This study only asked autistic adults about traumatic events on the LEC-5, which does not include other traumatic events such as bullying nor sensory trauma. It is possible that autistic adults interpreted the questions differently than non-autistic adults. More than half of our participants were White, so we know less about trauma experiences for autistic people from other racial and ethnic backgrounds.How will these findings help autistic adults now or in the future?The findings of this study provide useful information about how autistic adults experience traumatic events and PTSD symptoms, which is important for improving support services for autistic adults.</sec>
