Post-traumatic stress disorder in autistic and non-autistic adults: The impact of appraisals on reactions to traumatic events

Research suggests autistic people experience greater post-traumatic stress disorder symptom severity than non-autistic people following traumatic events. Post-trauma appraisals are fundamental in cognitive models of post-traumatic stress disorder, but have not been explored in autistic people. We aimed to explore whether we could replicate effects of heightened trauma exposure and post-traumatic stress disorder symptom severity in autistic adults, and examine how post-traumatic appraisals affect the association between autism and post-traumatic stress disorder symptom severity. Two hundred forty-two autistic (<i>n</i> = 148) and non-autistic adults (<i>n</i> = 94) completed a survey measuring trauma exposure, post-traumatic stress disorder symptom severity and post-trauma appraisals. Exposure to types of traumatic events did not differ significantly between the groups, but the autistic group endorsed more events that 'happened to me' directly. Post-traumatic stress disorder symptom severity and endorsement of negative post-traumatic appraisals were significantly higher in the autistic group, specifically alienation, shame and fear appraisals. These appraisals mediated the association between autism and post-traumatic stress disorder symptom severity. Therefore, as in the general population, greater endorsement of negative post-traumatic appraisals may be a risk factor for post-traumatic stress disorder symptom development in autistic adults, particularly appraisals of shame, fear and alienation. Longitudinal designs are required to confirm the direction of these effects and to elucidate factors underlying these negative appraisals in autistic people.Lay SummaryMany people experience intrusive memories and anxiety after a traumatic event. However, for some, these symptoms last longer and they might be diagnosed with post-traumatic stress disorder. Research suggests that autistic people might be more likely to develop post-traumatic stress disorder and experience more severe symptoms compared to non-autistic people after traumatic events. One factor that is important in post-traumatic stress disorder development is how people think about the trauma. These might be thoughts like 'It was my fault', 'I'm not safe', 'I'm disconnected from other people'. There has not been research into how autistic people think about traumatic events compared to non-autistic people, and this could be important for making post-traumatic stress disorder treatments more effective for them, as many of these focus on thoughts. In this study, we asked 148 autistic people and 94 non-autistic people in the United Kingdom to complete an online survey about their trauma history, post-traumatic stress disorder symptoms and thoughts about a traumatic event. We found that autistic people experienced more types of traumatic events directly (it happened to them), but they did not experience more types of traumatic events overall. Interestingly, both groups reported events like bullying or the death of a loved one as traumatic, but these events would not meet the official diagnostic criteria for post-traumatic stress disorder. As expected, autistic people reported worse post-traumatic stress disorder symptoms than non-autistic people and were more likely to meet the cut-off for post-traumatic stress disorder diagnosis. Autistic people also reported more negative thoughts about the trauma, especially feeling unsafe, disconnected, ashamed or that the trauma was their fault. Having more thoughts like this was associated with being autistic and experiencing more severe post-traumatic stress disorder symptoms. Our findings suggest that therapies focusing on these negative thoughts could be helpful for autistic people with post-traumatic stress disorder. Future research should explore why autistic people have more of these thoughts after traumatic events and should use longitudinal or experimental designs to explore how these factors influence one another over time. Efforts to prevent negative experiences, challenge negative attitudes in society towards autism and support positive autistic identity and well-being will be helpful for changing this in the future. It is also important that mental health services offer support for post-traumatic stress disorder even when events do not meet the current diagnostic criteria, as this might prevent autistic and non-autistic people who need support with post-traumatic stress disorder getting help.